#include <bits/stdc++.h>
using namespace std;

ifstream in("biconex.in");
ofstream out("biconex.out");

const int N=1e5;
struct graf
{
    vector<int> v;
} la[N+5];
int id,muchiiAfara,nrBiconex=0;
int ids[N+5],low[N+5];
bool punctArt[N+5];

void dfs(int rad,int nod,int tata)
{
    if(rad == tata) muchiiAfara++;

    ids[nod]=low[nod]=++id;

    for(int i=0; i<la[nod].v.size(); i++)
    {
        int to=la[nod].v[i];

        if(!ids[to])
        {
            dfs(rad,to,nod);
            low[nod]=min(low[nod],low[to]);
            if(ids[nod] <= low[to]) punctArt[nod]=1;
        }
        else low[nod]=min(low[nod],ids[to]);
    }
}

void detPuncteArt(int n)
{
    for(int i=1; i<=n; i++)
    {
        if(!ids[i])
        {
            muchiiAfara=0;
            dfs(i,i,-1);
            if(muchiiAfara>1) punctArt[i]=1;
        }
    }
    for(int i=1;i<=n;i++)
        if(punctArt[i]) nrBiconex++;
}

int main()
{
    int n,m;
    in>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int x,y;
        in>>x>>y;
        la[x].v.push_back(y);
        la[y].v.push_back(x);
    }

    detPuncteArt(n);
    cout<<nrBiconex<<'\n';
    return 0;
    for(int i=1;i<=n;i++)
    {
        if(punctArt[i] && low[i]!=i) cout<<low[i]<<' '<<i<<'\n';
        else
        {
            cout<<low[i]<<' ';
            if(low[i] == i) i++;
            while(!punctArt[i] && i<=n)
            {
                cout<<i<<' ';
                i++;
            }
            if(i<=n)cout<<i<<'\n';
            i--;
        }
    }
    for(int i=1; i<=n; i++)
        cout<<low[i]<<' ';
    cout<<'\n';
    for(int i=1; i<=n; i++)
        cout<<punctArt[i]<<' ';
    return 0;
}