#include <bits/stdc++.h>

using namespace std;

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

vector <int> g[100005];
int vizi[100005];
int n, m;

void df(int node)
{
    vizi[node] = 1;
    for(auto x : g[node])
    {
        if(vizi[x] == 1) continue;
        df(x);
    }
}

int main()
{
    int x, y;
    fin >> n >> m;
    for(int i=1; i<=m; ++i)
    {
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    int comp_con = 0;
    for(int i=1; i<=n; ++i)
    {
        if(vizi[i] == 1) continue;
        df(i);
        comp_con++;
    }

    fout << comp_con;
    return 0;
}