#include <fstream>
#include <vector>
using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

vector<int> adj[100001];
int viz[100001];
int boom,total;

void dfs(int nod){
    viz[nod] = 1;
    for(int i = 0; i<adj[nod].size();i++){
        if(!viz[adj[nod][i]]){dfs(adj[nod][i]); boom++;}
        else {total++; }
    }
}

int main()
{
    int N,M,i,x,y;
    fin>>N>>M;
    for(i = 0; i < M; i++){
        fin>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    for(i = 1; i <= N; i++){
        dfs(i);
        i = i+boom;
        boom = 0;
    }
    fout<<total-1;
}