#include <iostream>
#include <fstream>
#include <vector>
#define MAX 200001

using namespace std;

int n,m,r,x,y;
vector<int> nd[MAX];
bool acc[100001];
void dfs(int nod){
  acc[nod]=true;
  for(auto i:nd[nod])
    if(not acc[i]){
      acc[i]=true;
      dfs(i);
    }
}

int main()
{
    ifstream f ("dfs.in");
    ofstream g ("dfs.out");
    f>>n>>m;
    for(int i=1;i<=m;i++){
      f>>x>>y;
      nd[x].push_back(y);
      nd[y].push_back(x);
    }
    for(int i=1;i<=n;i++){
      if(not acc[i]){
        r++;
        dfs(i);
      }
    }
    g<<r;
    f.close ();
    g.close ();
    return 0;
}