using namespace std;
#include <vector>
#include <fstream>
#include<stdio.h>
#define max 100002
ifstream f("dfs.in");
ofstream g("dfs.out");
int N,M,X,Y;
int viz[max];
vector <int> graf[max];
 
void DFS(int nod){
int i;
viz[i]=1;
vector <int>::iterator it; 
  for (it=graf[nod].begin();it != graf[nod].end();it++)
    {
        viz[*it]=1;
    }
}

int main(){
int i,cnt=0;
f>>N>>M;
for (i=0;i<M;i++){
    f>>X>>Y;
    graf[X].push_back(Y);
    graf[Y].push_back(X);
    }
    

for (i=1;i<=N;++i)
if (viz[i]==0) {DFS(i);cnt++;}
g<<cnt;   
return 0;
}