#include <bits/stdc++.h>

using namespace std;

const int nmax = 100000;

int n,m;
bool viz[nmax+5];

vector <int> lg[nmax+5];

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

void dfs(int nod) {
  viz[nod] = true;
  for(auto it : lg[nod])
    if(!viz[it])
      dfs(it);
}

int main() {
  f >> n >> m;
  int x,y;
  for(int i=1; i<=n; i++) {
    f >> x >> y;
    lg[x].push_back(y);
    lg[y].push_back(x);
  }
  int nr = 0;
  for(int i=1; i<=n; i++)
    if(!viz[i]) {
      nr++;
      dfs(i);
    }
  g << nr;
  return 0;
}