#include <bits/stdc++.h>

using namespace std;

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

vector< int > lista[100005];
int viz[100005];
int n, m, x, y, nr;

void dfs( int nod ){

    viz[nod] = 1;
    for(unsigned int i = 0; i < lista[nod].size(); i++)
        if( viz[ lista[nod][i] ] == 0 )
            dfs( lista[nod][i] );

}

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

    for(int i = 1; i <= n; i++)
        if( viz[i] == 0 ){
            dfs(i);
            nr++;
        }

    out<<nr;

    return 0;
}