#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
using namespace std;
 
ifstream in("dfs.in");
ofstream out("dfs.out");

int n;
vector<int> G[100001];
bool viz[100001];

void DFS(int i);

int main(){
  
  int m;
  in>>n>>m;

  for(int i = 1; i <= m; i++){
    int x, y;
    in>>x>>y;
    G[x].push_back(y);
    G[y].push_back(x);
  }

  int k = 0;
  for(int i = 1; i <= n; i++){
    if(viz[i] == false){
      DFS(i);
      k++;
    }
  }

  out<<k;

  return 0;
}

void DFS(int i){
  stack<int> s;
  s.push(i);

  while(!s.empty()){
    int n = s.top();
    s.pop();
    viz[n] = true;

    for(int j = 0; j < G[n].size(); j++){
      int succ = G[n].at(j);
      if(viz[succ] == false){
        s.push(succ);
      }
    }

  }

}