#include <iostream>
#include <vector>
#include <fstream>

using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");

const int Nmax = 100005;
int n, m, Use[Nmax], Level[Nmax], Low[Nmax], punct[Nmax], nr;
vector <int> G[Nmax];

void DFS(int nod, int tata)
{
    Use[nod] = 1;
    int nrsons = 0;
    Level[nod] = Low[nod] = Level[tata]+1;
    for(int i = 0; i < (int)G[nod].size(); i++)
    {
        int vecin = G[nod][i];
        if(tata == vecin) continue;
        if(!Use[vecin])
        {
            nrsons++;
            DFS(vecin,nod);
            Low[nod] = min(Low[nod], Low[vecin]);
            if(Low[vecin] >= Level[nod] && tata > 0 && punct[nod] == 0)
            {
                punct[nod] = 1;
                nr++;
            }
        }
        else Low[nod] = min(Low[nod], Level[vecin]);
    }
    if(tata == 0 && nrsons > 1 && punct[nod] == 0)
    {
        punct[nod] = 1;
        nr++;
    }
}

int main()
{
    f>>n>>m;
    int sol = 0;
    while(m--)
    {
        int x,y;
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i = 1; i <= n; i++)
    {
        if(Use[i] == 0)
        {
            nr = 1;
            DFS(i,0);
            sol += nr;
        }
    }
    g<<sol<<'\n';
    return 0;
}