#include <bits/stdc++.h>
using namespace std;
const int MAX_CHARS = 256;
long long countDigit(long long n) { return floor(log10(n) + 1); }
long long ipow(long long base, long long exp) {
  long long result = 1;
  for (;;) {
    if (exp & 1) result *= base;
    exp >>= 1;
    if (!exp) break;
    base *= base;
  }
  return result;
}
long long divi(long long n) {
  long long r;
  if (n % 2 == 0) {
    return 2;
  }
  if (n % 3 == 0) {
    return 3;
  } else {
    r = floor(sqrt(n));
    long long d = 5;
    while ((n % d) && (d < n / d)) d += 2;
    if (n % d == 0)
      return d;
    else
      return n;
  }
}
int printmaxSubArraySum(int a[], int size) {
  int max_so_far = INT_MIN, max_ending_here = 0, start = 0, end = 0, s = 0;
  for (int i = 0; i < size; i++) {
    max_ending_here += a[i];
    if (max_so_far < max_ending_here) {
      max_so_far = max_ending_here;
      start = s;
      end = i;
    }
    if (max_ending_here < 0) {
      max_ending_here = 0;
      s = i + 1;
    }
  }
  cout << max_so_far << endl;
  cout << "Starting index " << start << endl << "Ending index " << end << endl;
}
bool isSubsetSum(int arr[], int n, int sum) {
  bool subset[2][sum + 1];
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j <= sum; j++) {
      if (j == 0)
        subset[i % 2][j] = true;
      else if (i == 0)
        subset[i % 2][j] = false;
      else if (arr[i - 1] <= j)
        subset[i % 2][j] =
            subset[(i + 1) % 2][j - arr[i - 1]] || subset[(i + 1) % 2][j];
      else
        subset[i % 2][j] = subset[(i + 1) % 2][j];
    }
  }
  return subset[n % 2][sum];
}
void printCharWithFreq(string str) {
  int n = str.size();
  int freq[26];
  memset(freq, 0, sizeof(freq));
  for (int i = 0; i < n; i++) freq[str[i] - 'a']++;
  for (int i = 0; i < n; i++) {
    if (freq[str[i] - 'a'] != 0) {
      cout << str[i] << freq[str[i] - 'a'] << " ";
      freq[str[i] - 'a'] = 0;
    }
  }
}
string evenlength(string n) {
  string res = n;
  for (int j = n.length() - 1; j >= 0; --j) res += n[j];
  return res;
}
long long mostFrequent(vector<long long> arr, long long n) {
  sort(arr.begin(), arr.end());
  long long max_count = 1, res = arr[0], curr_count = 1;
  for (long long i = 1; i < n; i++) {
    if (arr[i] == arr[i - 1])
      curr_count++;
    else {
      if (curr_count > max_count) {
        max_count = curr_count;
        res = arr[i - 1];
      }
      curr_count = 1;
    }
  }
  if (curr_count > max_count) {
    max_count = curr_count;
    res = arr[n - 1];
  }
  return res;
}
bool ck(int N) {
  if ((sqrt(N) - floor(sqrt(N))) != 0) return false;
  return true;
}
long long gcs(long long N) {
  if (ck(N)) {
    return N;
  }
  long long aboveN = -1, belowN = -1;
  long long n1;
  n1 = N + 1;
  while (true) {
    if (ck(n1)) {
      aboveN = n1;
      break;
    } else
      n1++;
  }
  return aboveN;
}
bool is_prime(long long n) {
  if (n == 1) {
    return false;
  }
  long long i = 2;
  while (i * i <= n) {
    if (n % i == 0) {
      return false;
    }
    i += 1;
  }
  return true;
}
long long leastPrimeFactor(long long n) {
  vector<int> least_prime(n + 1, 0);
  least_prime[1] = 1;
  for (int i = 2; i <= n; i++) {
    if (least_prime[i] == 0) {
      least_prime[i] = i;
      for (int j = 2 * i; j <= n; j += i)
        if (least_prime[j] == 0) least_prime[j] = i;
    }
  }
  return least_prime[n];
}
long long smallestDivisor(long long n) {
  if (n % 2 == 0) return 2;
  for (long long i = 3; i * i <= n; i += 2) {
    if (n % i == 0) return i;
  }
  return n;
}
long long countDistinct(long long arr[], long long n) {
  unordered_set<int> s;
  long long res = 0;
  for (long long i = 0; i < n; i++) {
    if (s.find(arr[i]) == s.end()) {
      s.insert(arr[i]);
      res++;
    }
  }
  return res;
}
void countFreq(long long arr[], long long n) {
  vector<long long> v;
  vector<bool> visited(n, false);
  for (long long i = 0; i < n; i++) {
    if (visited[i] == true) continue;
    long long count = 1;
    for (long long j = i + 1; j < n; j++) {
      if (arr[i] == arr[j]) {
        visited[j] = true;
        count++;
      }
    }
    v.push_back(count);
  }
  long long f = 0;
  for (long long i = 0; i < v.size(); i++) {
    cout << v[i] << " ";
    if (v[i] < 3) {
      f = 1;
    }
  }
  if (f == 1) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
}
long long mcm(long long p[], long long n) {
  long long m[n][n];
  long long j, k, q;
  for (long long i = 1; i < n; i++) {
    m[i][i] = 0;
  }
  for (long long L = 2; L < n; L++) {
    for (long long i = 1; i < n - L + 1; i++) {
      j = i + L - 1;
      m[i][j] = INT_MAX;
      for (k = i; k <= j - 1; k++) {
        q = m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j];
        if (q < m[i][j]) m[i][j] = q;
      }
    }
  }
  return m[1][n - 1];
}
long long lis(long long a[], long long n) {
  int lis[n];
  lis[0] = 1;
  for (int i = 1; i < n; i++) {
    lis[i] = 1;
    for (int j = 0; j < i; j++) {
      if (a[i] >= a[j] && lis[i] < lis[j] + 1) {
        lis[i] = lis[j] + 1;
      }
    }
  }
  sort(lis, lis + n);
}
bool isPerfectSquare(long double x) {
  long double sr = sqrt(x);
  return ((sr - floor(sr)) == 0);
}
long long findSubString(string str) {
  int n = str.length();
  int dist_count = 0;
  bool visited[MAX_CHARS] = {false};
  for (int i = 0; i < n; i++) {
    if (visited[str[i]] == false) {
      visited[str[i]] = true;
      dist_count++;
    }
  }
  int start = 0, start_index = -1, min_len = INT_MAX;
  int count = 0;
  int curr_count[MAX_CHARS] = {0};
  for (int j = 0; j < n; j++) {
    curr_count[str[j]]++;
    if (curr_count[str[j]] == 1) count++;
    if (count == dist_count) {
      while (curr_count[str[start]] > 1) {
        if (curr_count[str[start]] > 1) curr_count[str[start]]--;
        start++;
      }
      int len_window = j - start + 1;
      if (min_len > len_window) {
        min_len = len_window;
        start_index = start;
      }
    }
  }
  return str.substr(start_index, min_len).length();
}
int bs(long long arr[], long long l, long long r, long long x) {
  while (l <= r) {
    int m = l + (r - l) / 2;
    if (arr[m] == x) return m;
    if (arr[m] < x)
      l = m + 1;
    else
      r = m - 1;
  }
  return -1;
}
void cutrod(int n, int a[], int s) {
  int i;
  int dp[n + 1];
  for (i = 0; i < n + 1; i++) {
    dp[i] = INT_MIN;
  }
  dp[0] = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < s; j++)
      if (a[j] <= i) dp[i] = max(dp[i], dp[i - a[j]] + 1);
  }
  cout << dp[n] << endl;
}
int lcs2(string &X, string &Y) {
  int m = X.length(), n = Y.length();
  int L[2][n + 1];
  bool bi;
  for (int i = 0; i <= m; i++) {
    bi = i & 1;
    for (int j = 0; j <= n; j++) {
      if (i == 0 || j == 0)
        L[bi][j] = 0;
      else if (X[i - 1] == Y[j - 1])
        L[bi][j] = L[1 - bi][j - 1] + 1;
      else
        L[bi][j] = max(L[1 - bi][j], L[bi][j - 1]);
    }
  }
  return L[bi][n];
}
bool ckpal(string s, long long n) {
  for (long long i = 0; i < n; i++) {
    if (s[i] != s[n - i - 1]) {
      return false;
      break;
    }
  }
  return true;
}
bool is_reverse(string s1, string s2, long long m) {
  long long l1 = m;
  long long l2 = m;
  long long index = 0;
  if (index > l1 - 1) return true;
  if (l1 != l2 || s1[index] != s2[l2 - index - 1]) return false;
  ++index;
  return is_reverse(s1, s2, index);
}
bool compare(char arr1[], char arr2[]) {
  for (int i = 0; i < 256; i++)
    if (arr1[i] != arr2[i]) return false;
  return true;
}
bool search(string pat, string txt) {
  int M = pat.size(), N = txt.size();
  char countP[256] = {0}, countTW[256] = {0};
  for (int i = 0; i < M; i++) {
    (countP[pat[i]])++;
    (countTW[txt[i]])++;
  }
  for (int i = M; i < N; i++) {
    if (compare(countP, countTW)) return true;
    (countTW[txt[i]])++;
    countTW[txt[i - M]]--;
  }
  if (compare(countP, countTW)) return true;
  return false;
}
long long sd(long long n) {
  if (n % 2 == 0) return 2;
  for (long long i = 3; i * i <= n; i += 2) {
    if (n % i == 0) return i;
  }
  return n;
}
bool isorted(long long a[], long long n) {
  for (long long i = 0; i < n - 1; i++) {
    if (a[i] > a[i + 1]) {
      return false;
    }
  }
  return true;
}
bool isSubsetSum(long long arr[], long long n, long long sum) {
  bool subset[n + 1][sum + 1];
  for (int i = 0; i <= n; i++) subset[i][0] = true;
  for (int i = 1; i <= sum; i++) subset[0][i] = false;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= sum; j++) {
      if (j < arr[i - 1]) subset[i][j] = subset[i - 1][j];
      if (j >= arr[i - 1])
        subset[i][j] = subset[i - 1][j] || subset[i - 1][j - arr[i - 1]];
    }
  }
  return subset[n][sum];
}
int findMinRec(int arr[], int i, int sumCalculated, int sumTotal) {
  if (i == 0) return abs((sumTotal - sumCalculated) - sumCalculated);
  return min(findMinRec(arr, i - 1, sumCalculated + arr[i - 1], sumTotal),
             findMinRec(arr, i - 1, sumCalculated, sumTotal));
}
int findMin(int arr[], int n) {
  int sumTotal = 0;
  for (int i = 0; i < n; i++) sumTotal += arr[i];
  return findMinRec(arr, n, 0, sumTotal);
}
unsigned long long ceil(unsigned long long n, unsigned long long i) {
  if (n == 0) return 0;
  return (n - 1) / i + 1;
}
long long digisum(long long n) {
  long long s = 0;
  while (n != 0) {
    s += n % 10;
    n /= 10;
  }
  return s;
}
long long mio(vector<long long> v, long long n) {
  long long c = 0;
  for (long long i = 0; i < n; i++) {
    if (v[i] != -1) {
      c++;
    }
  }
  return c;
}
int count(int n) {
  int m = 3;
  int S[2] = {1, 2};
  int table[n + 1];
  memset(table, 0, sizeof(table));
  table[0] = 1;
  for (int i = 0; i < m; i++)
    for (int j = S[i]; j <= n; j++) table[j] += table[j - S[i]];
  return table[n];
}
long long maxHist(long long row[], long long C) {
  stack<long long> result;
  long long top_val;
  long long max_area = 0;
  long long area = 0;
  long long i = 0;
  while (i < C) {
    if (result.empty() || row[result.top()] <= row[i])
      result.push(i++);
    else {
      top_val = row[result.top()];
      result.pop();
      area = top_val * i;
      if (!result.empty()) area = top_val * (i - result.top() - 1);
      max_area = max(area, max_area);
    }
  }
  while (!result.empty()) {
    top_val = row[result.top()];
    result.pop();
    area = top_val * i;
    if (!result.empty()) area = top_val * (i - result.top() - 1);
    max_area = max(area, max_area);
  }
  return max_area;
}
int lenOfLongIncSubArr(int arr[], int n) {
  int max = 1, len = 1;
  for (int i = 1; i < n; i++) {
    if (arr[i] < arr[i - 1])
      len++;
    else {
      if (max < len) max = len;
      len = 1;
    }
  }
  if (max < len) max = len;
  return max;
}
int bitonic(int arr[], int n) {
  int inc[n];
  int dec[n];
  int i, max;
  inc[0] = 1;
  dec[n - 1] = 1;
  for (i = 1; i < n; i++) inc[i] = (arr[i] >= arr[i - 1]) ? inc[i - 1] + 1 : 1;
  for (i = n - 2; i >= 0; i--)
    dec[i] = (arr[i] >= arr[i + 1]) ? dec[i + 1] + 1 : 1;
  int len = 0;
  return lenOfLongIncSubArr(dec, n) + lenOfLongIncSubArr(inc, n) - 1;
}
int findBitonicSubarray(int A[], int n) {
  int I[n + 1];
  I[0] = 1;
  for (int i = 1; i <= n; i++) {
    I[i] = 1;
    if (A[i - 1] < A[i]) I[i] = I[i - 1] + 1;
  }
  int D[n + 1];
  D[n] = 1;
  for (int i = n - 1; i >= 0; i--) {
    D[i] = 1;
    if (A[i] > A[i + 1]) D[i] = D[i + 1] + 1;
  }
  int lbs_len = 1;
  int beg = 0, end = 0;
  for (int i = 0; i <= n; i++) {
    if (lbs_len < I[i] + D[i] - 1) {
      lbs_len = I[i] + D[i] - 1;
      beg = i - I[i] + 1;
      end = i + D[i] - 1;
    }
  }
  printf("The length of longest bitonic sub-array is %d\n", lbs_len);
  printf("The longest bitonic sub-array is [%d, %d]", beg, end);
  return lbs_len;
}
int maxSubArraySum(int a[], int size) {
  int max_so_far = 0, max_ending_here = 0;
  for (int i = 0; i < size; i++) {
    max_ending_here = max_ending_here + a[i];
    if (max_ending_here < 0)
      max_ending_here = 0;
    else if (max_so_far < max_ending_here)
      max_so_far = max_ending_here;
  }
  return max_so_far;
}
int main() {
  int t;
  t = 1;
  while (t--) {
    long long n, m;
    cin >> n >> m;
    long long c = 0;
    while (n >= 1 || m >= 1) {
      long long k = 0;
      if (n >= m && n >= 2 && m >= 1) {
        n -= 2;
        m -= 1;
        c++;
        k = 1;
      } else if (m > n && m >= 2 && n >= 1) {
        m -= 2;
        n -= 1;
        c++;
        k = 1;
      }
      if ((n <= 1 && m <= 1) || k == 0) {
        break;
      }
    }
    cout << c << endl;
  }
  return 0;
}

### Prompt

Develop a solution in Cpp to the problem described below:

A and B are preparing themselves for programming contests.

An important part of preparing for a competition is sharing programming knowledge from the experienced members to those who are just beginning to deal with the contests. Therefore, during the next team training A decided to make teams so that newbies are solving problems together with experienced participants.

A believes that the optimal team of three people should consist of one experienced participant and two newbies. Thus, each experienced participant can share the experience with a large number of people.

However, B believes that the optimal team should have two experienced members plus one newbie. Thus, each newbie can gain more knowledge and experience.

As a result, A and B have decided that all the teams during the training session should belong to one of the two types described above. Furthermore, they agree that the total number of teams should be as much as possible.

There are n experienced members and m newbies on the training session. Can you calculate what maximum number of teams can be formed?

Input

The first line contains two integers n and m (0 ≤ n, m ≤ 5·105) — the number of experienced participants and newbies that are present at the training session. 

Output

Print the maximum number of teams that can be formed.

Examples

Input

2 6


Output

2


Input

4 5


Output

3

Note

Let's represent the experienced players as XP and newbies as NB.

In the first test the teams look as follows: (XP, NB, NB), (XP, NB, NB).

In the second test sample the teams look as follows: (XP, NB, NB), (XP, NB, NB), (XP, XP, NB).

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
const int MAX_CHARS = 256;
long long countDigit(long long n) { return floor(log10(n) + 1); }
long long ipow(long long base, long long exp) {
  long long result = 1;
  for (;;) {
    if (exp & 1) result *= base;
    exp >>= 1;
    if (!exp) break;
    base *= base;
  }
  return result;
}
long long divi(long long n) {
  long long r;
  if (n % 2 == 0) {
    return 2;
  }
  if (n % 3 == 0) {
    return 3;
  } else {
    r = floor(sqrt(n));
    long long d = 5;
    while ((n % d) && (d < n / d)) d += 2;
    if (n % d == 0)
      return d;
    else
      return n;
  }
}
int printmaxSubArraySum(int a[], int size) {
  int max_so_far = INT_MIN, max_ending_here = 0, start = 0, end = 0, s = 0;
  for (int i = 0; i < size; i++) {
    max_ending_here += a[i];
    if (max_so_far < max_ending_here) {
      max_so_far = max_ending_here;
      start = s;
      end = i;
    }
    if (max_ending_here < 0) {
      max_ending_here = 0;
      s = i + 1;
    }
  }
  cout << max_so_far << endl;
  cout << "Starting index " << start << endl << "Ending index " << end << endl;
}
bool isSubsetSum(int arr[], int n, int sum) {
  bool subset[2][sum + 1];
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j <= sum; j++) {
      if (j == 0)
        subset[i % 2][j] = true;
      else if (i == 0)
        subset[i % 2][j] = false;
      else if (arr[i - 1] <= j)
        subset[i % 2][j] =
            subset[(i + 1) % 2][j - arr[i - 1]] || subset[(i + 1) % 2][j];
      else
        subset[i % 2][j] = subset[(i + 1) % 2][j];
    }
  }
  return subset[n % 2][sum];
}
void printCharWithFreq(string str) {
  int n = str.size();
  int freq[26];
  memset(freq, 0, sizeof(freq));
  for (int i = 0; i < n; i++) freq[str[i] - 'a']++;
  for (int i = 0; i < n; i++) {
    if (freq[str[i] - 'a'] != 0) {
      cout << str[i] << freq[str[i] - 'a'] << " ";
      freq[str[i] - 'a'] = 0;
    }
  }
}
string evenlength(string n) {
  string res = n;
  for (int j = n.length() - 1; j >= 0; --j) res += n[j];
  return res;
}
long long mostFrequent(vector<long long> arr, long long n) {
  sort(arr.begin(), arr.end());
  long long max_count = 1, res = arr[0], curr_count = 1;
  for (long long i = 1; i < n; i++) {
    if (arr[i] == arr[i - 1])
      curr_count++;
    else {
      if (curr_count > max_count) {
        max_count = curr_count;
        res = arr[i - 1];
      }
      curr_count = 1;
    }
  }
  if (curr_count > max_count) {
    max_count = curr_count;
    res = arr[n - 1];
  }
  return res;
}
bool ck(int N) {
  if ((sqrt(N) - floor(sqrt(N))) != 0) return false;
  return true;
}
long long gcs(long long N) {
  if (ck(N)) {
    return N;
  }
  long long aboveN = -1, belowN = -1;
  long long n1;
  n1 = N + 1;
  while (true) {
    if (ck(n1)) {
      aboveN = n1;
      break;
    } else
      n1++;
  }
  return aboveN;
}
bool is_prime(long long n) {
  if (n == 1) {
    return false;
  }
  long long i = 2;
  while (i * i <= n) {
    if (n % i == 0) {
      return false;
    }
    i += 1;
  }
  return true;
}
long long leastPrimeFactor(long long n) {
  vector<int> least_prime(n + 1, 0);
  least_prime[1] = 1;
  for (int i = 2; i <= n; i++) {
    if (least_prime[i] == 0) {
      least_prime[i] = i;
      for (int j = 2 * i; j <= n; j += i)
        if (least_prime[j] == 0) least_prime[j] = i;
    }
  }
  return least_prime[n];
}
long long smallestDivisor(long long n) {
  if (n % 2 == 0) return 2;
  for (long long i = 3; i * i <= n; i += 2) {
    if (n % i == 0) return i;
  }
  return n;
}
long long countDistinct(long long arr[], long long n) {
  unordered_set<int> s;
  long long res = 0;
  for (long long i = 0; i < n; i++) {
    if (s.find(arr[i]) == s.end()) {
      s.insert(arr[i]);
      res++;
    }
  }
  return res;
}
void countFreq(long long arr[], long long n) {
  vector<long long> v;
  vector<bool> visited(n, false);
  for (long long i = 0; i < n; i++) {
    if (visited[i] == true) continue;
    long long count = 1;
    for (long long j = i + 1; j < n; j++) {
      if (arr[i] == arr[j]) {
        visited[j] = true;
        count++;
      }
    }
    v.push_back(count);
  }
  long long f = 0;
  for (long long i = 0; i < v.size(); i++) {
    cout << v[i] << " ";
    if (v[i] < 3) {
      f = 1;
    }
  }
  if (f == 1) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
}
long long mcm(long long p[], long long n) {
  long long m[n][n];
  long long j, k, q;
  for (long long i = 1; i < n; i++) {
    m[i][i] = 0;
  }
  for (long long L = 2; L < n; L++) {
    for (long long i = 1; i < n - L + 1; i++) {
      j = i + L - 1;
      m[i][j] = INT_MAX;
      for (k = i; k <= j - 1; k++) {
        q = m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j];
        if (q < m[i][j]) m[i][j] = q;
      }
    }
  }
  return m[1][n - 1];
}
long long lis(long long a[], long long n) {
  int lis[n];
  lis[0] = 1;
  for (int i = 1; i < n; i++) {
    lis[i] = 1;
    for (int j = 0; j < i; j++) {
      if (a[i] >= a[j] && lis[i] < lis[j] + 1) {
        lis[i] = lis[j] + 1;
      }
    }
  }
  sort(lis, lis + n);
}
bool isPerfectSquare(long double x) {
  long double sr = sqrt(x);
  return ((sr - floor(sr)) == 0);
}
long long findSubString(string str) {
  int n = str.length();
  int dist_count = 0;
  bool visited[MAX_CHARS] = {false};
  for (int i = 0; i < n; i++) {
    if (visited[str[i]] == false) {
      visited[str[i]] = true;
      dist_count++;
    }
  }
  int start = 0, start_index = -1, min_len = INT_MAX;
  int count = 0;
  int curr_count[MAX_CHARS] = {0};
  for (int j = 0; j < n; j++) {
    curr_count[str[j]]++;
    if (curr_count[str[j]] == 1) count++;
    if (count == dist_count) {
      while (curr_count[str[start]] > 1) {
        if (curr_count[str[start]] > 1) curr_count[str[start]]--;
        start++;
      }
      int len_window = j - start + 1;
      if (min_len > len_window) {
        min_len = len_window;
        start_index = start;
      }
    }
  }
  return str.substr(start_index, min_len).length();
}
int bs(long long arr[], long long l, long long r, long long x) {
  while (l <= r) {
    int m = l + (r - l) / 2;
    if (arr[m] == x) return m;
    if (arr[m] < x)
      l = m + 1;
    else
      r = m - 1;
  }
  return -1;
}
void cutrod(int n, int a[], int s) {
  int i;
  int dp[n + 1];
  for (i = 0; i < n + 1; i++) {
    dp[i] = INT_MIN;
  }
  dp[0] = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < s; j++)
      if (a[j] <= i) dp[i] = max(dp[i], dp[i - a[j]] + 1);
  }
  cout << dp[n] << endl;
}
int lcs2(string &X, string &Y) {
  int m = X.length(), n = Y.length();
  int L[2][n + 1];
  bool bi;
  for (int i = 0; i <= m; i++) {
    bi = i & 1;
    for (int j = 0; j <= n; j++) {
      if (i == 0 || j == 0)
        L[bi][j] = 0;
      else if (X[i - 1] == Y[j - 1])
        L[bi][j] = L[1 - bi][j - 1] + 1;
      else
        L[bi][j] = max(L[1 - bi][j], L[bi][j - 1]);
    }
  }
  return L[bi][n];
}
bool ckpal(string s, long long n) {
  for (long long i = 0; i < n; i++) {
    if (s[i] != s[n - i - 1]) {
      return false;
      break;
    }
  }
  return true;
}
bool is_reverse(string s1, string s2, long long m) {
  long long l1 = m;
  long long l2 = m;
  long long index = 0;
  if (index > l1 - 1) return true;
  if (l1 != l2 || s1[index] != s2[l2 - index - 1]) return false;
  ++index;
  return is_reverse(s1, s2, index);
}
bool compare(char arr1[], char arr2[]) {
  for (int i = 0; i < 256; i++)
    if (arr1[i] != arr2[i]) return false;
  return true;
}
bool search(string pat, string txt) {
  int M = pat.size(), N = txt.size();
  char countP[256] = {0}, countTW[256] = {0};
  for (int i = 0; i < M; i++) {
    (countP[pat[i]])++;
    (countTW[txt[i]])++;
  }
  for (int i = M; i < N; i++) {
    if (compare(countP, countTW)) return true;
    (countTW[txt[i]])++;
    countTW[txt[i - M]]--;
  }
  if (compare(countP, countTW)) return true;
  return false;
}
long long sd(long long n) {
  if (n % 2 == 0) return 2;
  for (long long i = 3; i * i <= n; i += 2) {
    if (n % i == 0) return i;
  }
  return n;
}
bool isorted(long long a[], long long n) {
  for (long long i = 0; i < n - 1; i++) {
    if (a[i] > a[i + 1]) {
      return false;
    }
  }
  return true;
}
bool isSubsetSum(long long arr[], long long n, long long sum) {
  bool subset[n + 1][sum + 1];
  for (int i = 0; i <= n; i++) subset[i][0] = true;
  for (int i = 1; i <= sum; i++) subset[0][i] = false;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= sum; j++) {
      if (j < arr[i - 1]) subset[i][j] = subset[i - 1][j];
      if (j >= arr[i - 1])
        subset[i][j] = subset[i - 1][j] || subset[i - 1][j - arr[i - 1]];
    }
  }
  return subset[n][sum];
}
int findMinRec(int arr[], int i, int sumCalculated, int sumTotal) {
  if (i == 0) return abs((sumTotal - sumCalculated) - sumCalculated);
  return min(findMinRec(arr, i - 1, sumCalculated + arr[i - 1], sumTotal),
             findMinRec(arr, i - 1, sumCalculated, sumTotal));
}
int findMin(int arr[], int n) {
  int sumTotal = 0;
  for (int i = 0; i < n; i++) sumTotal += arr[i];
  return findMinRec(arr, n, 0, sumTotal);
}
unsigned long long ceil(unsigned long long n, unsigned long long i) {
  if (n == 0) return 0;
  return (n - 1) / i + 1;
}
long long digisum(long long n) {
  long long s = 0;
  while (n != 0) {
    s += n % 10;
    n /= 10;
  }
  return s;
}
long long mio(vector<long long> v, long long n) {
  long long c = 0;
  for (long long i = 0; i < n; i++) {
    if (v[i] != -1) {
      c++;
    }
  }
  return c;
}
int count(int n) {
  int m = 3;
  int S[2] = {1, 2};
  int table[n + 1];
  memset(table, 0, sizeof(table));
  table[0] = 1;
  for (int i = 0; i < m; i++)
    for (int j = S[i]; j <= n; j++) table[j] += table[j - S[i]];
  return table[n];
}
long long maxHist(long long row[], long long C) {
  stack<long long> result;
  long long top_val;
  long long max_area = 0;
  long long area = 0;
  long long i = 0;
  while (i < C) {
    if (result.empty() || row[result.top()] <= row[i])
      result.push(i++);
    else {
      top_val = row[result.top()];
      result.pop();
      area = top_val * i;
      if (!result.empty()) area = top_val * (i - result.top() - 1);
      max_area = max(area, max_area);
    }
  }
  while (!result.empty()) {
    top_val = row[result.top()];
    result.pop();
    area = top_val * i;
    if (!result.empty()) area = top_val * (i - result.top() - 1);
    max_area = max(area, max_area);
  }
  return max_area;
}
int lenOfLongIncSubArr(int arr[], int n) {
  int max = 1, len = 1;
  for (int i = 1; i < n; i++) {
    if (arr[i] < arr[i - 1])
      len++;
    else {
      if (max < len) max = len;
      len = 1;
    }
  }
  if (max < len) max = len;
  return max;
}
int bitonic(int arr[], int n) {
  int inc[n];
  int dec[n];
  int i, max;
  inc[0] = 1;
  dec[n - 1] = 1;
  for (i = 1; i < n; i++) inc[i] = (arr[i] >= arr[i - 1]) ? inc[i - 1] + 1 : 1;
  for (i = n - 2; i >= 0; i--)
    dec[i] = (arr[i] >= arr[i + 1]) ? dec[i + 1] + 1 : 1;
  int len = 0;
  return lenOfLongIncSubArr(dec, n) + lenOfLongIncSubArr(inc, n) - 1;
}
int findBitonicSubarray(int A[], int n) {
  int I[n + 1];
  I[0] = 1;
  for (int i = 1; i <= n; i++) {
    I[i] = 1;
    if (A[i - 1] < A[i]) I[i] = I[i - 1] + 1;
  }
  int D[n + 1];
  D[n] = 1;
  for (int i = n - 1; i >= 0; i--) {
    D[i] = 1;
    if (A[i] > A[i + 1]) D[i] = D[i + 1] + 1;
  }
  int lbs_len = 1;
  int beg = 0, end = 0;
  for (int i = 0; i <= n; i++) {
    if (lbs_len < I[i] + D[i] - 1) {
      lbs_len = I[i] + D[i] - 1;
      beg = i - I[i] + 1;
      end = i + D[i] - 1;
    }
  }
  printf("The length of longest bitonic sub-array is %d\n", lbs_len);
  printf("The longest bitonic sub-array is [%d, %d]", beg, end);
  return lbs_len;
}
int maxSubArraySum(int a[], int size) {
  int max_so_far = 0, max_ending_here = 0;
  for (int i = 0; i < size; i++) {
    max_ending_here = max_ending_here + a[i];
    if (max_ending_here < 0)
      max_ending_here = 0;
    else if (max_so_far < max_ending_here)
      max_so_far = max_ending_here;
  }
  return max_so_far;
}
int main() {
  int t;
  t = 1;
  while (t--) {
    long long n, m;
    cin >> n >> m;
    long long c = 0;
    while (n >= 1 || m >= 1) {
      long long k = 0;
      if (n >= m && n >= 2 && m >= 1) {
        n -= 2;
        m -= 1;
        c++;
        k = 1;
      } else if (m > n && m >= 2 && n >= 1) {
        m -= 2;
        n -= 1;
        c++;
        k = 1;
      }
      if ((n <= 1 && m <= 1) || k == 0) {
        break;
      }
    }
    cout << c << endl;
  }
  return 0;
}

```