#include<stdio.h>

struct entry
{
	int val;
	entry * adr;
}*start[102400], *stop[102400];

void add(int a, int b)
{
	entry *p;
	p=new entry;
	p->val=b;
	p->adr=NULL;
	if (start[a]==NULL)
		start[a]=stop[a]=p;
	else
	{
		stop[a]->adr=p;
		stop[a]=stop[a]->adr;
	}
	return;
}


int n, m;
char sel [102400];


void dfs(int nod)
{
	entry *p;
	sel[nod]=1;
	p=start[nod];
	while(p)
	{
		if (!sel[p->val])
			dfs(p->val);
		p=p->adr;
	}
	
}

int main()
{
	freopen("dfs.in", "r", stdin);
	freopen("dfs.out", "w", stdout);
	
	int i, a, b, sol=0;
	scanf("%d %d", &n, &m);
	for (i=1; i<=m; i++)
	{
		scanf("%d %d", &a, &b);
		add(a, b);
		add(b, a);
	}
	for (i=1; i<=n; i++)
	{
		if (!sel[i])
		{
			++sol;
			dfs(i);
		}
	}
	printf("%d\n", sol);	
	fclose(stdout);
	return 0;
}