#include <iostream>
#include <fstream>

using namespace std;

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

const int dim = 200005;

int vf[2*dim],urm[2*dim],lst[dim],nr,n,m,x,y,viz[dim];

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

void DFS(int x)
{
    viz[x] = 1;
    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);
    }
    int cnt = 0;
    for (int i=1; i<=n; i++)
    {
        if (!viz[i])
        {
           cnt++;
           DFS(i);
        }
    }
    out << cnt;
    return 0;
}