#include <bits/stdc++.h>

using namespace std;

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

vector <int> g[200005];
int v[200005];

void dfs(int nod)
{
    int n = g[nod].size();
    for (int i = 0; i < n; i ++) {
        int cn = g[nod][i];
        if (v[cn] == 0) {
            v[cn] = 1;
            dfs(cn);
        }
    }
}

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