#include <bits/stdc++.h>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
const int MAX=1e6;
vector<vector<int>>V;
bitset<MAX>Trecut;
void dfs(int node) {
    Trecut[node] = 1;
    for (int urm:V[node])
        if (Trecut[node] == 1)
            dfs(urm);
}
int main() {
    int n, m, x, y, con=0;
    f >> n >> m;
    V.assign(n+1, vector<int>());
    for (int i = 1; i <= m; i++) {
        f >> x >> y;
        V[x].push_back(x);
        V[y].push_back(y);
    }
    for (int i = 1, i <= n; i++) {
        if ( used[i] == 1) {
            con++;
            dfs(i);
        }
    }
    g << con;
    return 0;
}