#include <iostream>
#include <fstream>

using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

int n, m;

struct muchie{int n1, n2;}v[100001];

void citire()
    {
        f>>n>>m;
        for(int i=1; i<=m; i++)
            f>>v[i].n1>>v[i].n2;
    }

int viz[100001];

int caut(int nn1, int nn2)
    {
        for(int i=1; i<=n; i++)
            if(v[i].n1==nn1 && v[i].n2==nn2 || v[i].n1==nn2 && v[i].n2==nn1)
                return 1;
        return 0;
    }

void df(int vf, int nrc)
    {
        viz[vf]=1;
        for(int i=1; i<=n; i++)
        {
            if(viz[i]==0)
                if(caut(vf, i))
            {
                viz[i]=1;
                df(i, nrc);
            }
        }
    }

int main()
{
    citire();
    int nrc=1;
    int k=0;
    for(int i=1; i<=n; i++)
        if(viz[i]==0)
    {
        df(i, nrc);
        nrc++;
        k++;
    }
    g<<k;
}