#include <iostream>
#include <vector>

using namespace std;

const int NMAX = 1e6;
vector<int> g[NMAX];
bool use[NMAX];

void dfs (int Nod) {
    use[Nod] = 1;
    for (auto it : g[Nod])
        if (not use[it])
            dfs(it);
}

int main() {
    int n, m;
    cin >> n >> m;
    for (int x,y, i = 0; i < m; i++) {
        cin >> x >> y;
        g[x].push_back(y), g[y].push_back(x);
    }

    int ans = 0;
    for (int i = 0; i < n; i++)
        if (not use[i])
            dfs(i), ans++;

    cout << ans;
//    cout << dfs();

    return 0;
}