#include <bits/stdc++.h>
using namespace std;

vector <int> G[100005];
int n,nibab[100005],nr;

void Read(){

    int m,x,y;
    ifstream dfs("dfs.in");

    dfs>>n>>m;
    while (m--){
        dfs>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
        }
}
 void Dfs(int node){
     int i;
    nibab[node]=1;
    for (i=0;i<G[node].size();++i)
        if (!nibab[G[node][i]]) Dfs(G[node][i]);
}

void Write(){

    int i;
    ofstream dfs("dfs.out");
    for (i=1;i<=n;i++)
    if (!nibab[i]) {Dfs(i);nr++;}
    dfs<<nr;
}
int main()
{
    Read();
    Write();
    return 0;
}