#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

ifstream f("dfs.in");
ifstream g("dfs.out");

int N,M,n[200006],d[200006],viz[200006],cnt;
vector < int > adiacent[200006];

void dfsss(int nod)
{
    viz[nod]=1;
    for(int i=0;i<adiacent[nod].size();i=i+1){
        if(viz[adiacent[nod][i]]==0)
        {
            dfsss(adiacent[nod][i]);
        }
    }

}

int main()
{
    cin>>N>>M;
    for(int i=1;i<=N;i=i+1){
        cin>>n[i];
        cin>>d[i];
    }
    for(int i=1;i<=N;++i)
    {
        if(viz[i]==0)
        {
            dfsss(i);
            ++cnt;
        }
    }
    g<<cnt;
    return 0;
}