#include <iostream>
#include <vector>
#include <fstream>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

vector<int>L[100001];
int vis[100001];

void dfs(int node) {
    vis[node] = 1;
    for (auto vec : L[node]) {
        if (vis[vec] == 0) {
            dfs(vec);
        }
    }
}


int main() {
    int m, n;
    cin >> m>>n;
    for (int i = 1; i <= m; i++) {
        int a, b;
        fin >> a >> b;
        L[a].push_back(b);
        L[b].push_back(a);
    }
    int  nr = 0;
    for (int i = 0; i <= n; i++) {
        if (vis[i] == 0) {
            nr++;
            dfs(i);
        }
    }
    fout << nr;

    fin.close();
    return 0;

}