#include <bits/stdc++.h>
#define INfile "dfs.in"
#define OUTfile "dfs.out"
#define LMax 100001

using namespace std;

ifstream fin(INfile);
ofstream fout(OUTfile);

vector<int> v[LMax];
int x, y, n, m;
int nrcmp, verif[LMax];

void DFS(int i) {
    int urm, top = v[i].size();
    for (int j = 0; j < top; ++j) {
        urm = v[i][j];
        if (verif[urm] == 0) {
            verif[urm] = 1;
            DFS(urm);
        }
    }
}

int main() {
    fin >> n >> m;
    for (int i = 1; i <= m; ++i)
        fin >> x >> y, v[x].push_back(y), v[y].push_back(x);
    for (int i = 1; i <= n; ++i) {
        if (verif[i] == 0)
            DFS(i), nrcmp++;
    }
    fout << nrcmp;
    return 0;
}