#include <algorithm>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <time.h>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <numeric>
#include <limits>
#include <type_traits>

using namespace std;
#define SAY_YES cout << "YES" << endl;
#define SAY_Yes cout << "Yes" << endl;
#define SAY_NO cout << "NO" << endl;
#define SAY_No cout << "No" << endl;
#define IFYES(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "YES" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "NO" << endl;  \
    }
#define IFYes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "Yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "No" << endl;  \
    }
#define IFyes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "no" << endl;  \
    }
#define DEBUG_OUTPUT_ARRAY(XXX, ONE)                            \
    for (int i = 0; i < (ONE); i++)                             \
    {                                                           \
        cout << "DEBUG: i = " << i << " -> " << XXX[i] << endl; \
    }
#define DEBUG_OUTPUT_ARRAY2(XXX, ONE, TWO)                             \
    for (int i = 0; i < (ONE); i++)                                    \
    {                                                                  \
        cout << "<<< i = " << i << " >>>" << endl;                     \
        for (int j = 0; j < (TWO); j++)                                \
        {                                                              \
            cout << "DEBUG: j = " << j << " -> " << XXX[i][j] << endl; \
        }                                                              \
    }
#define DEBUG_OUTPUT_ARRAY2_BOX(XXX, ONE, TWO) \
    for (int i = 0; i < (ONE); i++)            \
    {                                          \
        cout << i << "  ";                     \
        for (int j = 0; j < (TWO); j++)        \
        {                                      \
            cout << XXX[i][j] << " ";          \
        }                                      \
        cout << endl;                          \
    }

typedef pair<long long int, long long int> pll;


const long long int mod = 1000000007;
const long long int INF = 1e18;
const long double PI=3.14159265358979323; 

long long int H,W,N,M,cou[10]={},res=0,a[100400],b[100400];
bool useH[200]={},useW[200]={};
string S[200000];


//union find木(グループわけができる)
class Union_Find{
	public:
	Union_Find(int MAX){
		par =new long long int[MAX+1];
		size =new long long int[MAX+1];
		for (int i = 0; i < MAX; i++) {
			par[i] = i;
            size[i]=1;
		}
	}
	long long int * par;
    long long int * size;
		//木の根を求める
	int unifind_root(int x) {
		if (par[x] == x) {
			return x;
		}
		else {
			return par[x] = unifind_root(par[x]);
		}
	}
		//同じグループか判定
	bool unifind_same(int x, int y) {
		return unifind_root(x) == unifind_root(y);
	}
		//グループ併合
	int unifind_unite(int x, int y) {
		x = unifind_root(x);
		y = unifind_root(y);
		if (x == y) {
			return 0;
		}
		par[x] = y;
        size[y] +=size[x];
	}
};

int main()
{
    cout << fixed << setprecision(18);
    cin>>N>>M;
	for(long long int i = 0; i < M; i++){
		cin>>a[i]>>b[i];
		a[i]--;
		b[i]--;
	}
	for(long long int i = 0; i < M; i++){
		Union_Find UF(N);
		for(long long int j = 0; j < M; j++){
			if(j==i){continue;}
			UF.unifind_unite(a[j],b[j]);
		}
		if(UF.size[UF.unifind_root(0)]!=N){res++;}
		//DEBUG_OUTPUT_ARRAY(UF.size,N);
	}
	cout<<res<<endl;
	
}


Measured memory_bytes: 1920