#include <bits/stdc++.h>
using namespace std;

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

int main()
{
    int n, m;
    fin >> n >> m;
    vector <int> adiacente[n+1]; 

    for (int i = 0; i < m; ++i)
    {
        int x, y;
        fin >> x >> y;
        adiacente[x].push_back(y);
        adiacente[y].push_back(x);
    }
    vector <int> visited(n+1, 0);
    stack <int> stiva;
    int culoare = 0;
    for(int i = 1; i <= n; ++i)
    {
        if(visited[i] == 0)
        {
            ++culoare;
            stiva.push(i);
            while(stiva.empty() == false)
            {
                int nod = stiva.top();
                stiva.pop();
                if(visited[nod] == 0)
                {
                    visited[nod] = culoare;
                    for(int vecin : adiacente[nod])
                        if(visited[vecin] == 0)
                            stiva.push(vecin);
                }
            }
        }
    }
    //for(int i = 1; i <= n; i++)
    //    cout << visited[i] << " ";
    //cout << endl;
    fout << culoare;
    return 0;
}