#include <bits/stdc++.h>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n, m, x, y;
bool fv[100005];
vector <int> v[100005];

void dfs(int i) {
    if (fv[i] == 0)
        return;
    fv[i] = 1;
    for (int j = 0; j < v[i].size(); ++j)
        dfs(v[i][j]);
    return;
}

int main() {
    fin >> n >> m;
    int maxim = 0;
    while (m--) {
        fin >> x >> y;
        maxim = max(x, maxim);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int rez = 0;
    for (int i = 1; i <= maxim; ++i) {
        if (fv[i] == 0) {
            ++rez;
            dfs(i);
        }
    }
    fout << rez;
    return 0;
}