#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,c,b;
int viz[100001],a[10001][10001],contor,k;
void df(int start, int &k)
{
    viz[start]=1;
    k++;///numarul de noduri legate intre ele
    for(int i=1;i<=n;i++)
        if(viz[i]==0 && a[start][i]==1)
            df(i,k);
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>c>>b;
        a[c][b]=a[b][c]=1;
    }
    for(int i=1;i<=n;i++)
    {
        k=0;
        if(viz[i]==0)///daca nu am vizitat nodul i
            df(i,k);///calculam numarul nodurilor din componenta conexa de care apartine nodul x
        if(k>0)
            contor++;
    }
    g<<contor;
    return 0;
}