#include <fstream>
#include <vector>

using namespace std;

ifstream cin("dfs.in");
ofstream cout("dfs.out");

#define DIM 100001

vector <int> v[DIM];
int n, m, nr, x, y, sel[DIM];

static inline void dfs(int k) {
    sel[k] = 1;
    for(auto e : v[k])
        if(sel[e] == 0)
            dfs(e);
}

int main() {
    cin >> n >> m;
    for(int i = 1; i <= n; i++) {
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

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

    cout << nr;

    return 0;
}