#include<fstream>

using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

int a[2000][2000],n,m,viz[2000],cc;

void citire(){
	in>>n>>m;
	for(int i=1;i<=m;i++){
		int x,y;
		in>>x>>y;
		a[x][y]=a[y][x]=1;
	}
}

void df(int nod){
	//out<<nod<<" ";
	for(int i=1;i<=n;i++)
		if(a[nod][i]==1 && viz[i]==0){
			//out<<i<<" ";
			viz[i]=1;
			df(i);
		}
}

int main(){
	citire();
	for(int i=1;i<=n;i++)
		if(!viz[i]){
			cc++;
			viz[i]=1;
			df(i);
		}
	out<<cc;
	return 0;
}