#include <cstdio>

#define MaxN 100010

struct nod{
	int inf;
	nod *urm;}*L[MaxN];
	
int N,M,s[MaxN],Nr;


void add(int x,int y)
{
	nod *q=new nod;
	q->inf=y;
	q->urm=L[x];
	L[x]=q;
}

void cit()
{
	int i,x,y;
	scanf("%d%d",&N,&M);
	for(i=1;i<=M;i++)
	{
		scanf("%d%d",&x,&y);
		add(x,y);
		add(y,x);
	}
}

void dfs(int k)
{
	nod *q=new nod;
	s[k]=1;
	for(q=L[k];q;q=q->urm)
		if(!s[q->inf])
			dfs(q->inf);
}

void solve()
{
	int i;
	Nr=0;
	for(i=1;i<=N;i++)
		if(!s[i])
		{
			Nr++;
			dfs(i);
		}
	printf("%d\n",Nr);
}

int main()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	cit();
	solve();
	fclose(stdin);
	fclose(stdout);
	return 0;
}