#include <iostream>
#include <vector>
#include <fstream>
#include <algorithm>
#include <queue>

using namespace std;

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

vector <int> Graf[100001];
int viz[100001];


void dfs(int node)
{
    if (viz[node] == 1)
        return;
    viz[node] = 1;
    for (auto i : Graf[node])
        dfs(i);
}

int main() {
    int n, m,a, b,rez=0;
    fin >> n >> m;
    for (int i = 0; i < m; i++)
    {
        fin >> a >> b;
        Graf[a].push_back(b);
        Graf[b].push_back(a);
    }
    for (int i = 1; i <= n; i++)
    {
        if (viz[i] != 1)
        {
            dfs(i);
            rez++;
        }
    }
    fout << rez;

    return 0;
}