#include<stdio.h>
#include<stdlib.h>
#include<vector>
using namespace std;
vector <int> vecini[100000];
int v[200000],n,m;
void citire(){
    int i, x, y;
    
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	scanf("%d %d",&n,&m);

	for (i=1;i<=m;i++){
		scanf("%d %d",&x,&y);
		vecini[x].push_back(y);
		vecini[y].push_back(x);
	}
}
void DF(int k){
     for(int i=0;i<vecini[k].size();i++)
       if(!v[vecini[k][i]]){
          v[vecini[k][i]]=1;
          DF(vecini[k][i]);
       }
}
int main(){
    int nr=0;
    citire();
    for (int i=1;i<=n;i++) if (!v[i]) { nr++; DF(i);}
	printf("%d\n",nr);
	
    return 0;
}