#include <bits/stdc++.h>
#define INFILE "dfs.in"
#define OUTFILE "dfs.out"
#define DIM 100005

using namespace std;

ifstream f(INFILE);
ofstream g(OUTFILE);

int n, m, nrComp;
vector <int> edges[DIM];
bitset <DIM> visited;

void dfs(int node) {
    visited[node] = 1;

    for (auto k: edges[node]) {
        if (!visited[k]) {
            visited[k] = 1;
            dfs(k);
        }
    }
}

int main() {

    f >> n >> m;

    for (int i = 1; i <= n; i++) {
        int x, y;
        f >> x >> y;
        edges[x].push_back(y);
        edges[y].push_back(x);
    }

    for (int i = 1; i <= n; i++) {
        if (visited[i] == 0) {
            dfs(i);
            nrComp++;
        }
    }

    g << nrComp;

    return 0;

}