#include <vector>
#include <fstream>
#include <cstdlib>
#define N_MAX 100011

using namespace std;
bool was[N_MAX];
vector< int > G[N_MAX];
inline void DFS( int x )
{
    was[x]=true;
    vector< int >::const_iterator it=G[x].begin(), iend=G[x].end();
    for( ; it < iend; ++it )
        if( false == was[*it] )
            DFS(*it);
}
int main(void)
{
    int N, M, x, y;
    ifstream in( "dfs.in");
    for( in>>N>>M; M; --M )
    {
        in>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for( x=1, y=0; x <= N; ++x )
        if( false == was[x] )
        {
            DFS(x);
            ++y;
        }
    ofstream out( "dfs.out" );
    out<<y<<'\n';
    return EXIT_SUCCESS;
}