At first, let's define function f(x) as follows: $$$ \begin{matrix} f(x) & = & \left\{ \begin{matrix} x/2 & \mbox{if } x  is even \\\ x - 1 & \mbox{otherwise } \end{matrix} \right. \end{matrix} $$$

We can see that if we choose some value v and will apply function f to it, then apply f to f(v), and so on, we'll eventually get 1. Let's write down all values we get in this process in a list and denote this list as path(v). For example, path(1) = [1], path(15) = [15, 14, 7, 6, 3, 2, 1], path(32) = [32, 16, 8, 4, 2, 1].

Let's write all lists path(x) for every x from 1 to n. The question is next: what is the maximum value y such that y is contained in at least k different lists path(x)?

Formally speaking, you need to find maximum y such that \left| \{ x ~|~ 1 ≤ x ≤ n, y ∈ path(x) \} \right| ≥ k.

Input

The first line contains two integers n and k (1 ≤ k ≤ n ≤ 10^{18}).

Output

Print the only integer — the maximum value that is contained in at least k paths.

Examples

Input


11 3


Output


5


Input


11 6


Output


4


Input


20 20


Output


1


Input


14 5


Output


6


Input


1000000 100


Output


31248

Note

In the first example, the answer is 5, since 5 occurs in path(5), path(10) and path(11).

In the second example, the answer is 4, since 4 occurs in path(4), path(5), path(8), path(9), path(10) and path(11).

In the third example n = k, so the answer is 1, since 1 is the only number occuring in all paths for integers from 1 to 20.
#include <bits/stdc++.h>
using namespace std;
template <class T>
void chmin(T& a, const T& b) {
  if (a > b) a = b;
}
template <class T>
void chmax(T& a, const T& b) {
  if (a < b) a = b;
}
template <class T>
using MaxHeap = priority_queue<T>;
template <class T>
using MinHeap = priority_queue<T, vector<T>, greater<T> >;
template <class T, class U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
  os << p.first << ',' << p.second;
  return os;
}
template <class T, class U>
istream& operator>>(istream& is, pair<T, U>& p) {
  is >> p.first >> p.second;
  return is;
}
template <class T>
ostream& operator<<(ostream& os, const vector<T>& vec) {
  for (int i = 0; i < vec.size(); i++) {
    os << vec[i];
    if (i + 1 < vec.size()) os << ' ';
  }
  return os;
}
template <class T>
istream& operator>>(istream& is, vector<T>& vec) {
  for (int i = 0; i < vec.size(); i++) is >> vec[i];
  return is;
}
void fastio() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  cout << fixed << setprecision(20);
}
const long long MOD = 1000000007ll;
struct ModInt {
  long long val;
  ModInt() : val(0ll) {}
  ModInt(const long long& v) : val(((v % MOD) + MOD) % MOD) {}
  ModInt exp(long long y) const {
    if (!y) return ModInt(1ll);
    ModInt a = exp(y / 2ll);
    a *= a;
    if (y & 1) a *= (*this);
    return a;
  }
  bool operator==(const ModInt& x) const { return val == x.val; }
  inline bool operator!=(const ModInt& x) const { return !(*this == x); }
  bool operator<(const ModInt& x) const { return val < x.val; }
  bool operator>(const ModInt& x) const { return val > x.val; }
  inline bool operator>=(const ModInt& x) const { return !(*this < x); }
  inline bool operator<=(const ModInt& x) const { return !(*this > x); }
  ModInt& operator+=(const ModInt& x) {
    if ((val += x.val) >= MOD) val -= MOD;
    return *this;
  }
  ModInt& operator-=(const ModInt& x) {
    if ((val += MOD - x.val) >= MOD) val -= MOD;
    return *this;
  }
  ModInt& operator*=(const ModInt& x) {
    (val *= x.val) %= MOD;
    return *this;
  }
  ModInt operator+(const ModInt& x) const { return ModInt(*this) += x; }
  ModInt operator-(const ModInt& x) const { return ModInt(*this) -= x; }
  ModInt operator*(const ModInt& x) const { return ModInt(*this) *= x; }
  friend istream& operator>>(istream& i, ModInt& x) {
    long long v;
    i >> v;
    x = v;
    return i;
  }
  friend ostream& operator<<(ostream& o, const ModInt& x) {
    o << x.val;
    return o;
  }
};
ModInt pow(ModInt a, long long x) {
  ModInt res = ModInt(1ll);
  while (x) {
    if (x & 1) res *= a;
    x >>= 1;
    a = a * a;
  }
  return res;
}
vector<ModInt> inv, fac, facinv;
ModInt nCr(int n, int r) {
  assert(!(n < r));
  assert(!(n < 0 || r < 0));
  return fac[n] * facinv[r] * facinv[n - r];
}
void init(int SIZE) {
  fac.resize(SIZE + 10);
  inv.resize(SIZE + 10);
  facinv.resize(SIZE + 10);
  fac[0] = ModInt(1ll);
  for (int i = 1; i <= SIZE; i++) fac[i] = fac[i - 1] * ModInt(i);
  inv[1] = ModInt(1ll);
  for (int i = 2; i <= SIZE; i++)
    inv[i] = ModInt(0ll) - ModInt(MOD / i) * inv[MOD % i];
  facinv[0] = ModInt(1ll);
  for (int i = 1; i <= SIZE; i++) facinv[i] = facinv[i - 1] * inv[i];
  return;
}
long long n, k;
long long oddf(long long x) {
  long long w = 1ll;
  long long res = 0ll;
  while (1) {
    if (n < x) break;
    if (n < x + w) {
      res += (n - x + 1);
      break;
    } else {
      res += w;
    }
    x *= 2ll;
    w *= 2ll;
  }
  return res;
}
long long evenf(long long x) {
  long long w = 2ll;
  long long res = 0ll;
  while (1) {
    if (n < x) break;
    if (n < x + w) {
      res += (n - x + 1);
      break;
    } else {
      res += w;
    }
    x *= 2ll;
    w *= 2ll;
  }
  return res;
}
long long even() {
  long long l = 0ll, r = n;
  r /= 2ll;
  r++;
  while (r - l > 1ll) {
    long long mid = (l + r) / 2ll;
    if (evenf(mid * 2ll) >= k)
      l = mid;
    else
      r = mid;
  }
  return l * 2ll;
}
long long odd() {
  long long l = 0ll, r = n;
  r = (r + 1) / 2ll;
  while (r - l > 1ll) {
    long long mid = (l + r) / 2ll;
    if (oddf(2 * mid + 1ll) >= k)
      l = mid;
    else
      r = mid;
  }
  return 2ll * l + 1ll;
}
signed main() {
  fastio();
  cin >> n >> k;
  cout << max(odd(), even()) << endl;
  return 0;
}
