#pragma GCC optimize ("Ofast")
#include<bits/stdc++.h>
using namespace std;
void *wmem;
template<class T> inline void walloc1d(T **arr, int x, void **mem = &wmem){
  static int skip[16]={0, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
  (*mem) = (void*)( ((char*)(*mem)) + skip[((unsigned long long)(*mem)) & 15] );
  (*arr)=(T*)(*mem);
  (*mem)=((*arr)+x);
}
inline void rd(int &x){
  int k, m=0;
  x=0;
  for(;;){
    k = getchar_unlocked();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = getchar_unlocked();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
inline void wt_L(char a){
  putchar_unlocked(a);
}
inline void wt_L(int x){
  char f[10];
  int m=0, s=0;
  if(x<0){
    m=1;
    x=-x;
  }
  while(x){
    f[s++]=x%10;
    x/=10;
  }
  if(!s){
    f[s++]=0;
  }
  if(m){
    putchar_unlocked('-');
  }
  while(s--){
    putchar_unlocked(f[s]+'0');
  }
}
struct graph{
  int N, **edge, *es;
  void setEdge(int N__, int M, int A[], int B[], void **mem = &wmem){
    int i;
    N = N__;
    walloc1d(&es, N, mem);
    walloc1d(&edge, N, mem);
    for(i=0;i<(N);i++){
      es[i] = 0;
    }
    for(i=0;i<(M);i++){
      es[A[i]]++;
      es[B[i]]++;
    }
    for(i=0;i<(N);i++){
      walloc1d(&edge[i], es[i], mem);
    }
    for(i=0;i<(N);i++){
      es[i] = 0;
    }
    for(i=0;i<(M);i++){
      edge[A[i]][es[A[i]]++] = B[i];
      edge[B[i]][es[B[i]]++] = A[i];
    }
  }
  inline void bccDFS(int v, int u, int *res, int *rt, int &rts, int *S, int &Ss, int *inS, int *num, int &tm){
    int i, k;
    num[v] = ++tm;
    S[Ss++] = v;
    inS[v] = 1;
    rt[rts++] = v;
    for(i=0;i<(es[v]);i++){
      int w=edge[v][i];
      if(!num[w]){
        bccDFS(w, v, res, rt, rts, S, Ss, inS, num, tm);
      }
      else if(u != w && inS[w]){
        while(num[rt[rts-1]] > num[w]){
          rts--;
        }
      }
    }
    if(v == rt[rts-1]){
      k = S[Ss-1];
      for(;;){
        int w=S[--Ss];
        inS[w] = 0;
        res[w] = k;
        if(v==w){
          break;
        }
      }
      rts--;
    }
  }
  int bcc(int res[], void *mem=wmem){
    int *S, Ss=0, i, *inS, k, *num, *rt, rts=0, tm=0;
    pair<int,int> *arr;
    walloc1d(&num, N, &mem);
    walloc1d(&rt, N, &mem);
    walloc1d(&S, N, &mem);
    walloc1d(&inS, N, &mem);
    memset(num, 0, sizeof(int)*N);
    memset(inS, 0, sizeof(int)*N);
    for(i=0;i<(N);i++){
      if(!num[i]){
        bccDFS(i, N, res, rt, rts, S, Ss, inS, num, tm);
      }
    }
    arr = (pair<int,int>*)mem;
    for(i=0;i<(N);i++){
      arr[i].first = res[i];
      arr[i].second = i;
    }
    sort(arr, arr+N);
    k = 0;
    for(i=0;i<(N);i++){
      if(i && arr[i].first != arr[i-1].first){
        k++;
      }
      res[arr[i].second] = k;
    }
    return k+1;
  }
}
;
char memarr[96000000];
int N;
int M;
int A[50];
int B[50];
graph g;
int c[50];
int main(){
  int i, res=0;
  wmem = memarr;
  rd(N);
  rd(M);
  {
    int Lj4PdHRW;
    for(Lj4PdHRW=0;Lj4PdHRW<(M);Lj4PdHRW++){
      rd(A[Lj4PdHRW]);A[Lj4PdHRW] += (-1);
      rd(B[Lj4PdHRW]);B[Lj4PdHRW] += (-1);
    }
  }
  g.setEdge(N,M,A,B);
  g.bcc(c);
  for(i=0;i<(M);i++){
    if(c[A[i]]!=c[B[i]]){
      res++;
    }
  }
  wt_L(res);
  wt_L('\n');
  return 0;
}
// cLay varsion 20190902-1

// --- original code ---
// int N, M, A[50], B[50];
// 
// graph g;
// int c[50];
// {
//   int res = 0;
//   rd(N,M,(A--,B--)(M));
//   g.setEdge(N,M,A,B);
//   g.bcc(c);
//   rep(i,M) if(c[A[i]]!=c[B[i]]) res++;
//   wt(res);
// }


Measured memory_bytes: 256