#include <bits/stdc++.h>

using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,x,y;
int c[100001];
int nrc;
int main()
{
    f>>n>>m;
    nrc = n;
    for(int i=1;i<=n;++i)
        c[i] = i;
    for(int i=1;i<=m;++i)
    {
        f>>x>>y;
        if(c[x]!=c[y])
        {
            --nrc;
            int maxim = max(c[x],c[y]);
            int minim = min(c[x],c[y]);

            for(int i=1;i<=n;++i)
                if(c[i] == maxim) c[i] = minim;
        }
    }
    g<<nrc;
    return 0;
}