#include <bits/stdc++.h>
using namespace std;	
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);
	scanf("%d %d",&n,&m);
	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\n",cnt);
	return 0;
}