/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

#ifndef MAJK_LIB
#define MAJK_LIB

#include <vector>
#include <stack>
#include <iostream>
#include <unordered_map>
#include <map>
#include <iomanip>
#include <set>
#include <functional>
#include <fstream>
#include <algorithm>
#include <cassert>
#include <cmath>
#include <string>
#include <sstream>
#include <queue>
#include <bitset>
using namespace std;

#define x first
#define y second
typedef std::pair<int,int> pii; typedef long long ll; typedef unsigned long long ull; typedef unsigned int ui;

template <typename T, typename U> std::istream&operator>>(std::istream&i, pair<T,U>&p) {i >> p.x >> p.y; return i;}
template<typename T>std::istream&operator>>(std::istream&i,vector<T>&t) {for(auto&v:t){i>>v;}return i;}
template<typename T>std::ostream&operator<<(std::ostream&o,const vector<T>&t) {for(size_t i=0;i<t.size();++i){o<<t[i]<<" \n"[i == t.size()-1];}return o;}
template<typename T> using minheap = priority_queue<T, vector<T>, greater<T>>;
template<typename T> using maxheap = priority_queue<T, vector<T>, less<T>>;
auto fraclt = [](const pii&a,const pii&b) { return (ll)a.x * b.y < (ll)b.x * a.y; };
struct cmpfrac { bool operator()(const pii&a,const pii&b)const { return (ll)a.x * b.y < (ll)b.x * a.y; }};
template <typename T> bool in(T a, T b, T c) { return a <= b && b < c; }
ui logceil(ll x) {ui b=0;while(x){x>>=1;++b;}return b;}

namespace std {
    template<typename T,typename U>struct hash<pair<T,U>>{hash<T>t;hash<U>u;size_t operator()(const pair<T,U>&p)const{return t(p.x)^(u(p.y)<<7);}};
}
template<typename T,typename F>T bsh(T l,T h,const F&f){T r=-1,m;while(l<=h){m=(l+h)/2;if(f(m)){l=m+1;r=m;}else{h=m-1;}}return r;}
template<typename F> double bsh(double l,double h,const F&f,double p=1e-9){ui r=3+(ui)log2((h-l)/p);while(r--){double m=(l+h)/2;if(f(m)){l=m;}else{h=m;}}return (l+h)/2;}
template<typename T,typename F>T bsl(T l,T h,const F&f){T r=-1,m;while(l<=h){m=(l+h)/2;if(f(m)){h=m-1;r=m;}else{l=m+1;}}return r;}
template<typename F> double bsl(double l,double h,const F&f,double p=1e-9){ui r=3+(ui)log2((h-l)/p);while(r--){double m=(l+h)/2;if(f(m)){h=m;}else{l=m;}}return (l+h)/2;}
template<typename T> T gcd(T a,T b) { if (a<b) swap(a,b); return b?gcd(b,a%b):a; }

template<typename T>class vector2:public vector<vector<T>>{public:vector2(){} vector2(size_t a,size_t b,T t=T()):vector<vector<T>>(a,vector<T>(b,t)){}};
template<typename T>class vector3:public vector<vector<vector<T>>>{public:vector3(){} vector3(size_t a,size_t b,size_t c,T t=T()):vector<vector<vector<T>>>(a,vector<vector<T>>(b,vector<T>(c,t))){}};
template <typename T> struct bounded_priority_queue {
	inline bounded_priority_queue(ui X) : A(X), B(0) {}
	inline void push(ui L, T V) { B = max(B, L); A[L].push(V); }
	inline const T &top() const { return A[B].front(); }
	inline void pop() { A[B].pop(); while (B > 0 && A[B].empty()) --B; }
	inline bool empty() const { return A[B].empty(); }
	inline void clear() { B = 0; for (auto &a: A) a = queue<T>(); }
private:
	vector<queue<T>> A; ui B;
};


#endif


struct Graph {
    explicit Graph(const vector<vector<int>> &E):E(E),N(E.size()) {}

    void prep_dfs(){V=vector<bool>(N,false);D=P=L=vector<int>(N,-1);T=0;}
    void bridges(vector<pii>&br){prep_dfs();for(int i=0;i<N;i++)if(!V[i])_bridge_dfs(br,i);}
    void _bridge_dfs(vector<pii>&br,int u){
        L[u]=D[u]=T++;V[u]=true;
        for(int v:E[u]) {
            if(!V[v]){
                P[v]=u;
                _bridge_dfs(br, v);
                L[u]=min(L[u],L[v]);
                if(L[v]>D[u])br.push_back({u,v});
            }else if(P[u]!=v)L[u]=min(L[u], D[v]);
        }
    }

    void artic(vector<bool>&art){prep_dfs();for(int i=0;i<N;i++)if(!V[i])_artic_dfs(art,i);}
    void _artic_dfs(vector<bool>&art,int u){
        L[u]=D[u]=T++;V[u]=true;int c=0;art[u]=false;
        for(int v:E[u]) {
            if(!V[v]){
                P[v]=u;
                _artic_dfs(art, v);
                L[u]=min(L[u],L[v]);
                if((P[v]==-1&&++c>1)||(P[v]!=-1&&L[v]>=D[u]))art[u]=true;
            }else if(P[u]!=v)L[u]=min(L[u], D[v]);
        }
    }
    const vector<vector<int>>&E;int N,T;
    vector<bool>V;vector<int>L,P,D;
};
// #include "../l/mod.h"

class bridges {
public:
    void solve(istream& cin, ostream& cout) {
        int N,M;cin>>N>>M;
        vector<vector<int>> E(N);
        for (int i = 0; i < M; ++i) {
            int a,b; cin >> a>>b;--a;--b;
            E[a].push_back(b);
            E[b].push_back(a);
        }
        Graph G{E};
        vector<pii> B;
        G.bridges(B);
        cout << B.size() << endl;

    }
};


int main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
	bridges solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
    return 0;
}


Measured memory_bytes: 256