#include<stdio.h>
#define maxn 100010
int viz[maxn],*vec[maxn],nr[maxn],n,m,conex;
struct vecin{
	int x,y;
};
vecin a[2*maxn];
void df(int i){
	int j;
	viz[i]=1;
	for(j=1;j<=vec[i][0];++j){
		if(!viz[vec[i][j]])
			df(vec[i][j]);
	}
}
void citire(){
	int i;
	scanf("%d%d",&n,&m);
	for(i=0;i<m;++i){
		scanf("%d%d",&a[i].x,&a[i].y);
		++nr[a[i].x];
		++nr[a[i].y];
	}
	for(i=1;i<=n;++i){
		vec[i]=new int (nr[i]+1);
		vec[i][0]=0;
	}
	for(i=0;i<m;++i){
		vec[a[i].x][++vec[a[i].x][0]]=a[i].y;
		vec[a[i].y][++vec[a[i].y][0]]=a[i].x;
	}
}
int main(){
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	int i;
	citire();
	conex=0;
	for(i=1;i<=n;++i){
		if(!viz[i]){
			++conex;
			df(i);
		}
	}
	
	printf("%d\n",conex);
	
	fclose(stdin);
	fclose(stdout);
	return 0;
}