#include <fstream>
#include <vector>

using namespace std;

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

const int NMax = 100005;
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(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]==0){
        DFS(i);  Sol++;}
      }
    Print();
    return 0;
}