Drzewka FINAL VERSION :D

#include<algorithm>
#include<vector>
#include <iostream>
#include <cstdio>
using namespace std;
int wynik =0;
typedef vector<int >   VI;
const int INF = 1000000000;

int n,m, cnt;
VI in, pi;
vector<VI> adj;


void read()
{
    int i, a,b;
    scanf("%d %d", &n, &m);
    adj.clear(); adj.resize(n);
    for (i=0; i<m; i++)
    {
        scanf("%d %d", &a, &b);
        if (a==b) continue;
        a--; b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
}


void init()
{
    in.clear (); in.resize (n,INF);
    pi.resize(n);
    cnt = 1;
}

int dfs(int u)
{
    int ans = u;
    in[u] = cnt++;
    for (int i=0; i<adj[u].size(); i++)
    {
        int v = adj[u][i];

        if (v==u) continue;

        if (v==pi[u]) continue;

        if (in[v]==INF)
        {
            pi[v] = u;
            v = dfs(v);
        }
        if (in[ans] > in[v]) ans=v;
    }
    if (ans==u && pi[u]!=u) wynik++;

    return ans;
}

int main(void)
{
    read();
    init();
    for (int u=0; u<n; u++)
        if (in[u]==INF)
        {
            pi[u] = u; dfs(u);
        }
    cout << wynik;
    return 0;
}