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

vector < int > g[1<<20];
bool vis[1<<20];
int n, m, c;

void dfs(int u) {
    vis[u] = true;
    for (auto v : g[u]) if (!vis[v]) dfs(v);
}

int main() {
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for (int i = 0; i < n; i++) if (!vis[i]) c++, dfs(i);
    cout << c;
    return 0;
}