#include <fstream>
#include <vector>
#define NMax 100005
using namespace std;

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

int N,M,Sol;
vector< int > G[NMax];

int Use[NMax];

void Read()
{
    fin>>N>>M;
    for(int i=1;i<=M;i++)
        {
            int x,y;
            fin>>x>>y;
            G[x].push_back(y);
            G[y].push_back(x);
        }
}

void DFS(int Nod)
{
  Use[Nod] = 1;
  for(unsigned int i=0; i<G[Nod].size();i++)
    {
        int Vecin = G[Nod][i];
        if(!Use[Vecin])
            DFS(Vecin);
    }

}

void Print()
{
   fout<<Sol<<"\n";
}

int main()
{
    Read();

    for(int i=1;i<=N;i++)
        if(!Use[i])
            {
                Sol++;
                DFS(i);
            }

    Print();
    return 0;
}