#include <bits/stdc++.h>
using namespace std;
vector<int> adj[100001];
void dfs(int node, vector<int> &viz) {
    viz[node] = 1;
    for(int neigh : adj[node]) {
        if(!viz[neigh]) {
            viz[neigh] = 1;
            dfs(neigh, viz);
        }
    }
}
int main() {
    ifstream in("dfs.in");
    ofstream out("dfs.out");
   
    int n, m, a, b;
    in >> n >> m;
    for(int i = 0; i < n; i++) {
        in >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    vector<int> viz(n + 1, 0);
    int ans = 0;
    for(int i = 1; i <= n; i++) {
        if(!viz[i]) {
            dfs(i, viz);
            ans++;
        }
    }
    out << ans;
    
}