#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long n_ = 1e5 + 1000;
const long double PI = acos(-1.0);
long long gcd(long long a, long long b) { return (a ? gcd(b % a, a) : b); }
long long power(long long a, long long n) {
  long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
long long power(long long a, long long n, long long mod) {
  long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
      p %= mod;
    }
    n >>= 1;
    a *= a;
    a %= mod;
  }
  return p % mod;
}
bool vowel(char ch) {
  if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u')
    return true;
  else
    return false;
}
class UnionFind {
 private:
  vector<long long> p, rank, setSize;
  long long numSets;

 public:
  UnionFind(long long N) {
    setSize.assign(N, 1);
    numSets = N;
    rank.assign(N, 0);
    p.assign(N, 0);
    for (long long i = 0; i < N; i++) p[i] = i;
  }
  long long findSet(long long i) {
    return (p[i] == i) ? i : (p[i] = findSet(p[i]));
  }
  bool isSameSet(long long i, long long j) { return findSet(i) == findSet(j); }
  void unionSet(long long i, long long j) {
    if (!isSameSet(i, j)) {
      numSets--;
      long long x = findSet(i), y = findSet(j);
      if (rank[x] > rank[y]) {
        p[y] = x;
        setSize[x] += setSize[y];
      } else {
        p[x] = y;
        setSize[y] += setSize[x];
        if (rank[x] == rank[y]) rank[y]++;
      }
    }
  }
  long long numDisjointSets() { return numSets; }
  long long sizeOfSet(long long i) { return setSize[findSet(i)]; }
};
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, m, s, x;
  cin >> n >> m;
  vector<long long> vec[n];
  long long cnt = 0;
  for (long long i = 0; i < n; i++) {
    cin >> s;
    for (long long j = 0; j < s; j++) {
      cin >> x;
      vec[i].push_back(x);
    }
  }
  for (long long i = 0; i < n; i++) cnt += vec[i].size();
  if (cnt == 0) {
    cout << n;
    return 0;
  }
  UnionFind UF(n);
  for (long long i = 0; i < n; i++) {
    for (long long j = i + 1; j < n; j++) {
      if (vec[i].size() == 0 || vec[j].size() == 0) continue;
      for (long long a = 0; a < vec[i].size(); a++) {
        for (long long b = 0; b < vec[j].size(); b++) {
          if (vec[i][a] == vec[j][b]) UF.unionSet(i, j);
        }
      }
    }
  }
  cout << UF.numDisjointSets() - 1;
  return 0;
}

### Prompt

Create a solution in Cpp for the following problem:

The "BerCorp" company has got n employees. These employees can use m approved official languages for the formal correspondence. The languages are numbered with integers from 1 to m. For each employee we have the list of languages, which he knows. This list could be empty, i. e. an employee may know no official languages. But the employees are willing to learn any number of official languages, as long as the company pays their lessons. A study course in one language for one employee costs 1 berdollar.

Find the minimum sum of money the company needs to spend so as any employee could correspond to any other one (their correspondence can be indirect, i. e. other employees can help out translating).

Input

The first line contains two integers n and m (2 ≤ n, m ≤ 100) — the number of employees and the number of languages.

Then n lines follow — each employee's language list. At the beginning of the i-th line is integer ki (0 ≤ ki ≤ m) — the number of languages the i-th employee knows. Next, the i-th line contains ki integers — aij (1 ≤ aij ≤ m) — the identifiers of languages the i-th employee knows. It is guaranteed that all the identifiers in one list are distinct. Note that an employee may know zero languages.

The numbers in the lines are separated by single spaces.

Output

Print a single integer — the minimum amount of money to pay so that in the end every employee could write a letter to every other one (other employees can help out translating).

Examples

Input

5 5
1 2
2 2 3
2 3 4
2 4 5
1 5


Output

0


Input

8 7
0
3 1 2 3
1 1
2 5 4
2 6 7
1 3
2 7 4
1 1


Output

2


Input

2 2
1 2
0


Output

1

Note

In the second sample the employee 1 can learn language 2, and employee 8 can learn language 4.

In the third sample employee 2 must learn language 2.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long n_ = 1e5 + 1000;
const long double PI = acos(-1.0);
long long gcd(long long a, long long b) { return (a ? gcd(b % a, a) : b); }
long long power(long long a, long long n) {
  long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
long long power(long long a, long long n, long long mod) {
  long long p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
      p %= mod;
    }
    n >>= 1;
    a *= a;
    a %= mod;
  }
  return p % mod;
}
bool vowel(char ch) {
  if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u')
    return true;
  else
    return false;
}
class UnionFind {
 private:
  vector<long long> p, rank, setSize;
  long long numSets;

 public:
  UnionFind(long long N) {
    setSize.assign(N, 1);
    numSets = N;
    rank.assign(N, 0);
    p.assign(N, 0);
    for (long long i = 0; i < N; i++) p[i] = i;
  }
  long long findSet(long long i) {
    return (p[i] == i) ? i : (p[i] = findSet(p[i]));
  }
  bool isSameSet(long long i, long long j) { return findSet(i) == findSet(j); }
  void unionSet(long long i, long long j) {
    if (!isSameSet(i, j)) {
      numSets--;
      long long x = findSet(i), y = findSet(j);
      if (rank[x] > rank[y]) {
        p[y] = x;
        setSize[x] += setSize[y];
      } else {
        p[x] = y;
        setSize[y] += setSize[x];
        if (rank[x] == rank[y]) rank[y]++;
      }
    }
  }
  long long numDisjointSets() { return numSets; }
  long long sizeOfSet(long long i) { return setSize[findSet(i)]; }
};
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, m, s, x;
  cin >> n >> m;
  vector<long long> vec[n];
  long long cnt = 0;
  for (long long i = 0; i < n; i++) {
    cin >> s;
    for (long long j = 0; j < s; j++) {
      cin >> x;
      vec[i].push_back(x);
    }
  }
  for (long long i = 0; i < n; i++) cnt += vec[i].size();
  if (cnt == 0) {
    cout << n;
    return 0;
  }
  UnionFind UF(n);
  for (long long i = 0; i < n; i++) {
    for (long long j = i + 1; j < n; j++) {
      if (vec[i].size() == 0 || vec[j].size() == 0) continue;
      for (long long a = 0; a < vec[i].size(); a++) {
        for (long long b = 0; b < vec[j].size(); b++) {
          if (vec[i][a] == vec[j][b]) UF.unionSet(i, j);
        }
      }
    }
  }
  cout << UF.numDisjointSets() - 1;
  return 0;
}

```