#include <bits/stdc++.h>

using namespace std;

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

int n, m;

int main()
{
    fin >> n >> m;
    vector < vector < int > > graph(n + 1);
    bool viz[n + 1] = {0};
    for(int i = 1 ; i <= m ; i++)
    {
        int x, y;
        fin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    std::function<void(int)> dfs = [&](int nod)
    {
        viz[nod] = 1;
        for (auto& it : graph[nod])
            if (!viz[it])
            {
                ///std::cout << it << " ";
                dfs(it);
            }
    };
    int ans = 0;
    for(int i = 1 ; i <= n ; i++)
        if(!viz[i])
    {
        ans++;
        dfs(i);
    }
    fout << ans << "\n";
    fin.close();
    fout.close();
    return 0;
}