#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream in ("dfs.in");
ofstream out ("dfs.out");
vector <long> v[200002];
long n,m,i,x,y,viz[200002],nr;
void df (long k)
{
    long i;
    viz[k]=1;
    long nod=k;
    for(i=0;i<v[nod].size();i++)
    {
        if(!viz[v[nod][i]])
        {
            df(v[nod][i]);
        }
    }

}
int main()
{
in>>n>>m;
for(i=1;i<=n;i++)
{
    in>>x>>y;
    v[x].push_back(y);
    v[y].push_back(x);
}
for(i=1;i<=n;i++)
{
    if(!viz[i])
    {
        df(i);
        nr++;
    }
}
out<<nr;
    return 0;
}