#include <stdio.h>

int n, m, viz[100005], cnt;

typedef struct nod
{
	int x;
	nod *a;
} *pNod;
pNod v[100005];

void add(pNod &dest, int val)
{
	pNod p;
	p = new nod;
	p->x = val;
	p->a = dest;
	dest = p;
}

void citire()
{
	freopen("dfs.in", "r", stdin);
	freopen("dfs.out", "w", stdout);
	int i, x, y;

	for(i=1;i<=m;i++)
	{
		scanf("%d %d", &x, &y);
		add(v[x], y);
		add(v[y], x);
	}
}

void DFS(int nod)
{
	pNod p;
	viz[nod] = 1;
	for(p=v[nod];p!=NULL;p=p->a)
		if(!viz[p->x])
			DFS(p->x);
}

int main()
{
	citire();
	int i;
	for(i=1;i<=n;i++)
		if(!viz[i])
		{
			cnt++;
			DFS(i);
		}
	printf("%d", cnt);
	return 0;
}