#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

vector <int> a[100001];
bool v[100001];
int n;

void DFS(int k)
{
    v[k] = true;
    int M = a[k].size();
    for (int i = 0; i < M; i++)
        if (!v[a[k][i]])
            DFS(i);
}

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