#include <bits/stdc++.h>

using namespace std;

vector <int> L[100001];
ifstream f("dfs.in");
ofstream g("dfs.out");

int viz[100001];

void DFS(int nod) {
    viz[nod] = 1;
    for (auto& vecin: L[nod])
        if (viz[vecin] == 0) {
            DFS(vecin);
        }
}
int main() {
    int n, m, x, y;
    int nr = 0;
    f >> n >> m;
    for (int i=1; i<=m; i++) {
        f >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    for (int i=1; i<=n; i++) {
        sort(L[i].begin(), L[i].end());
    }
    for(int i=1;i<=n;i++)
        if(viz[i]==0){
            nr++;
            DFS(i);
        }
    g << nr;
    return 0;
}