#include <bits/stdc++.h>
#define whlie while
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define rep(i,N) for(int i = 0; i < (N); i++)
#define repr(i,N) for(int i = (N) - 1; i >= 0; i--)
#define rep1(i,N) for(int i = 1; i <= (N) ; i++)
#define repr1(i,N) for(int i = (N) ; i > 0 ; i--)
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
#define vrep(v,it) for(auto it = v.begin(); it != v.end(); it++)
#define vrepr(v,it) for(auto it = v.rbegin(); it != v.rend(); it++)
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
using namespace std; void solve();
using ll = long long; using vl = vector<ll>;
using vi = vector<int>; using vvi = vector< vector<int> >;
constexpr int inf = 1001001001;
constexpr ll infLL = (1LL << 61) - 1;
struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7);} } iosetupnya;
template<typename T, typename U> inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template<typename T, typename U> inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; }
template<typename T, typename U> ostream& operator <<(ostream& os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<typename T, typename U> istream& operator >>(istream& is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<typename T> ostream& operator <<(ostream& os, const vector<T> &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; }
template<typename T> istream& operator >>(istream& is, vector<T> &v) { for(auto &x : v) is >> x; return is; }
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#ifdef NyaanDebug
  #include "NyaanDebug.h"
  #define trc(...) do { cerr << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0)
  #define trca(v,N) do { cerr << #v << " = "; array_out(v , N);cout << endl;} while(0)
#else
  #define trc(...)
  #define trca(...)
  int main(){solve();}
#endif

using P = pair<double,double>; using vp = vector<P>;
constexpr int MOD = /**/ 1000000007; //*/ 998244353;
/////////////////

// LowLink, 橋と関節点の列挙 
// 橋(bridge) 取り除くとグラフを分断する辺
// 関節点(articulation point) 取り除くとグラフを分断する節点
template<typename T>
struct LowLink{
  int N;
  const T &g;
  vector<int> ord , low , articulation;
  vector<pair<int,int> > bridge;
  LowLink(const T &g) : g(g){
    N = g.size();
    ord.resize(N , -1);
    low.resize(N , -1);
    articulation.reserve(N);
    bridge.reserve(N);
    int k = 0;
    for(int i = 0; i < N; i++){
      if(!(~ord[i])) k = dfs(i , k , -1);
    }
    articulation.shrink_to_fit();
    bridge.shrink_to_fit();
  }
  int dfs(int idx , int k , int par){
    low[idx] = (ord[idx] = k++);
    int cnt = 0;
    bool is_arti = false;
    for(auto &to : g[idx]){
      if(ord[to] == -1){
        cnt++;
        k = dfs(to , k , idx);
        low[idx] = min(low[idx] , low[to]);
        is_arti |= (par != -1) && (low[to] >= ord[idx]);
        if(ord[idx] < low[to]){
          bridge.emplace_back(minmax(idx , (int)to));
        }
      }
      else if(to != par){
        low[idx] = min(low[idx] , ord[to]);
      }
    }
    is_arti |= par == -1 && cnt > 1;
    if(is_arti) articulation.push_back(idx);
    return k;
  }
};

void solve(){
  ini(N , M);
  vvi g(N);
  rep(i , M){
    ini(x,y);
    x--; y--;
    g[x].pb(y);
    g[y].pb(x);
  }
  LowLink<decltype(g)> low(g);
  trc(low.bridge);
  out(sz(low.bridge));
}

Measured memory_bytes: 256