#include<iostream>
#include<stdio.h>
struct nod {int inf;nod *next;} *a[100010];
int n,m,i,ut[100010],nr,x,y;
void add(nod *&v,int y)
{
	nod *c=new nod;
	c->inf=y;
	c->next=v;
	v=c;
}
void dfs(int nd)
{
	ut[nd]=1;
	nod *p;
	for(p=a[nd];p;p=p->next)
		if(!ut[p->inf])
			dfs(p->inf);
}
int main()
{
	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);
		add(a[x],y);
		add(a[y],x);
	}
	for(i=1;i<=n;i++)
		if(!ut[i])
		{
			nr++;
			dfs(i);
		}
	printf("%d\n",nr);
	return 0;
}