#include <stdio.h>

int n, m, viz[100009], cnt;

typedef struct nod
{int x; nod *a; } *pNod;
pNod v[100009];

void cit()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	scanf("%d %d",&n,&m);
	int i, x, y;
	pNod p;
	
	for (i = 1; i <= m; i++)
	{
		scanf("%d %d",&x,&y);
		p = new nod;
		p -> x = x;
		p -> a = v[y];
		v[y] = p;
		p = new nod;
		p -> x = y;
		p -> a = v[x];
		v[x] = p;
	}
}

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