#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,c,b;
int viz[100001],contor,T[2][400001],Start[100001];
void df(int nodstart)
{
    int man;
    viz[nodstart]=1;
    man=Start[nodstart];
    while(man)
    {
        if(viz[T[0][man]]==0)
            df(T[0][man]);
        man=T[1][man];
    }
}
int main()
{
    int k=0;
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>c>>b;
        k++;
        T[0][k]=b;
        T[1][k]=Start[c];
        Start[c]=k;
        k++;
        T[0][k]=c;
        T[1][k]=Start[b];
        Start[b]=k;
    }
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)///daca nu am vizitat nodul i
        {
            df(i);///vizitam componentele legate de el
            contor++;///avem o componenta conexa noua
        }
    }
    g<<contor;
    return 0;
}