#include<bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
typedef long long ll;
#define rep(i,n) for(ll i=0, i##_len=(n); i<i##_len; ++i)
#define REP(i,num,n) for(ll i=num, i##_len=(n); i<i##_len; ++i)
#define repprev(i,a,b) for(int i=b-1;i>=a;i--)
#define reprev(i,n) repprev(i,0,n)
using namespace std;
#define sz(x) ((int)(x).size())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define MEMSET(v, h) memset((v), h, sizeof(v))
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define pb push_back
#define mp make_pair
#define y0 y3487465
#define y1 y8687969
#define j0 j1347829
#define j1 j234892
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
const ll INF = 1LL<<60;
 
const int MAX = 510000;
const int MOD = 1000000007;
 
long long fac[MAX], finv[MAX], inv[MAX];
 
// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}
 
// 二項係数計算
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
 
struct UnionFind {
    vector<ll> par;
 
    UnionFind(ll n) : par(n, -1) { }
    void init(ll n) { par.assign(n, -1); }
 
    ll root(ll x) {
        if (par[x] < 0) return x;
        else return par[x] = root(par[x]);
    }
 
    bool issame(ll x, ll y) {
        return root(x) == root(y);
    }
 
    bool merge(ll x, ll y) {
        x = root(x); y = root(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y); // merge technique
        par[x] += par[y];
        par[y] = x;
        return true;
    }
 
    ll size(ll x) {
        return -par[root(x)];
    }
};

template <typename T>
vector<T> dijkstra(int s,vector<vector<pair<int, T> > > & G){
   const T INF = numeric_limits<T>::max();
   using P = pair<T, int>;
   int n=G.size();
   vector<T> d(n,INF);
   vector<int> b(n,-1);
   priority_queue<P,vector<P>,greater<P> > q;
   d[s]=0;
   q.emplace(d[s],s);
   while(!q.empty()){
     P p=q.top();q.pop();
     int v=p.second;
     if(d[v]<p.first) continue;
     for(auto& e:G[v]){
       int u=e.first;
       T c=e.second;
       if(d[u]>d[v]+c){
         d[u]=d[v]+c;
         b[u]=v;
         q.emplace(d[u],u);
       }
     }
   }
   return d;
}


const int limit = 50;

ll n, m;
ll a[limit], b[limit];

bool graph[limit][limit];
bool visited[limit];

int dfs(ll v){
  visited[v] = true;
  rep(v2,n){
    if(graph[v][v2] == false) continue;
    if(visited[v2] == true) continue;
    dfs(v2);
  }
}

int main() {
	cin >> n >> m;
	vector<ll> A(m), B(m);
	rep(i, m) {
		cin >> A[i] >> B[i];
		A[i]--;
		B[i]--;
      	graph[A[i]][B[i]] = graph[B[i]][A[i]] = true;
	}

	ll ans = 0;
  
  	rep(i,m){
      graph[A[i]][B[i]] = graph[B[i]][A[i]] = false;
      rep(j,n) visited[j] = false;
      
      dfs(0);
      
      bool bridge = false;
      rep(j,n) if(!visited[j]) bridge = true;
      if(bridge) ++ans;
      
      graph[A[i]][B[i]] = graph[B[i]][A[i]] = true;
    }

	cout << ans << endl;

}


Measured memory_bytes: 256