#include <cstdio>
#include <vector>
#include <algorithm>

#define NMAX 100005

using namespace std;

vector < long > g[NMAX];
vector < long > dfs_disc,dfs_low,art_vrt,dfs_parent;
long rootChild,n,m,dfsRoot,time,u,v,cnt,newv[NMAX],viz[NMAX];

void art_point (long u)
{
    long j,v;
    time++;
    dfs_disc[u]=dfs_low[u]=time;
    for(j=0;j<g[u].size();j++)
    {
        v=g[u][j];
        if(!dfs_disc[v]){
            dfs_parent[v]=u;
            if(u==dfsRoot)
                rootChild++;
            art_point(v);
            if(dfs_low[v]>=dfs_disc[u])
                art_vrt[u]=true;
            dfs_low[u]=min(dfs_low[u],dfs_disc[v]);
        }
        else if(v!=dfs_parent[u])
            dfs_low[u]=min(dfs_low[u],dfs_disc[v]);
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);

    scanf("%ld%ld",&n,&m);

    for(long i=1;i<=m;i++)
    {
        scanf("%ld%ld",&u,&v);
        g[u].push_back(v);
        g[v].push_back(u);
    }

    dfs_parent.assign(n+1,-1);
    art_vrt.assign(n+1,0);
    dfs_low.assign(n+1,0);
    dfs_disc.assign(n+1,0);

    for(long i=1;i<=n;i++)
    {
        if(!dfs_disc[i])
        {
            dfsRoot=i,rootChild=0;
            art_point(i);
            art_vrt[dfsRoot]=(rootChild>1);
        }
    }

    for(long i=1;i<=n;i++)
        if(art_vrt[i])
            cnt++;

    printf("%ld\n",cnt);

    return 0;
}

/*void makevrt(long u){

    long i,j,v;
    newv[++newv[0]]=u;
    viz[u]=poz;
    for(i=0;i<g[i].size();i++)
    {
        v=g[u][i];
        if(viz[v]!=poz)
        {
            if(!art_vrt[v])
                makevrt(v);
            else {
                newv[++newv[0]]=v;
                viz[v]=poz;
            }
        }
    }
}
*/
    /*long poz=0;
    for(long i=1;i<=n;i++)
    {
        if(art_vrt[i])
        {
            poz++;

        }
    }*/