#include <iostream>
#include<bits/stdc++.h>

using namespace std;
int n,m,x,y,a,b,i,j,v[100005],rad,cod,nr,ok;
int radacina(int x)
{
    while(v[x]!=0)x=v[x];
    return x;
}
ifstream f("dfs.in");
ofstream g("dfs.out");
int main()
{
    f>>n>>m;
    nr=n;
    for(i=1; i<=m; i++)
    {


        f>>x>>y;

        if (radacina(x)!=radacina(y))

        {
            nr--;
            v[radacina(x)]=radacina(y);


        }

    }g<<nr;
}