#include <bits/stdc++.h>

using namespace std;

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

const int MAX = 400003;

int n,m,lst[MAX],urm[MAX],vf[MAX],nr,how_many,x,y;
bool viz[MAX];

void adauga(int x, int y)
{
    vf[++nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs(int x)
{
    viz[x] = true;
    for(int p = lst[x]; p != 0; p = urm[p])
    {
        int y = vf[p];
        if(!viz[y])
        {
            dfs(y);
        }
    }
}

int main()
{
    in >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        in >> x >> y;
        adauga(x, y);
        adauga(y, x);
    }
    for(int i = 1; i <= n; i++)
    {
        if(viz[i] == 0)
        {
            how_many++;
            dfs(i);
        }
    }
    out << how_many;
    return 0;
}