#include<iostream.h>
#include<fstream.h>
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,x,y,a[1000][1000],nr,i,j,viz[1000];
void citire(){
	f>>n>>m;
	while(f>>x>>y)
		a[x][y]=a[y][x]=1;
}
void dfs(int c){
	int i;
	viz[c]=nr;
	for(i=1;i<=n;i++)
	  if(a[i][c]&&!viz[i])
		  dfs(i);
}

int main(){
	citire();
	for(i=1;i<=n;i++)
		if(!viz[i]){
			dfs(i);
			nr++;
		}

g<<nr;
}