#include <fstream>
#include <vector>
using namespace std;

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

const int NMAX = 100005;
vector <int>G[NMAX];
int Use[NMAX];
int N,M,Sol;

void Read(){
  in >> N >> M;
  int x, y;
  for(int i = 0; i < M; ++i)
  {
    in >> x >> y;
    G[x].push_back(y);
    G[y].push_back(x);
  }
}

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

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

int main()
{
    Read();
    for(int i = 1; i <= N; ++i)
      if(!Use[i])
      {
        Sol++;
        DFS(i);
      }
    Print();
    return 0;
}