#include <iostream>
#include<cstdio>
#include<vector>
using namespace std;
vector <int> v[100005];
bool viz[100005];
void dfs(int x){
  int i;
  viz[x]=true;
  for(i=0;i<v[x].size();i++){
    if(viz[v[x][i]]==false)
      dfs(v[x][i]);
  }
}
int main()
{
    FILE*fin,*fout;
    fin=fopen("dfs.in","r");
    fout=fopen("dfs.out","w");
    int n,m,x1,x2,compc=0,i;
    fscanf(fin,"%d%d",&n,&m);
    for(i=1;i<=n;i++){
      fscanf(fin,"%d%d",&x1,&x2);
      v[x1].push_back(x2);
      v[x2].push_back(x1);
    }
    for(i=1;i<=n;i++){
      if(viz[i]==false){
        compc++;
        dfs(i);
      }
    }
    fprintf(fout,"%d",compc);
    return 0;
}