#include<stdio.h>
int a[200005];
int used[200005];
int main()
{
	int n;
	scanf("%d", &n);
	int i, j;
	for (i = 0; i < n; i++)
	{
		scanf("%d", &a[i]);
		a[i]--;
	}
	for (i = 0; i < n; i++)
		used[i] = -1;
	int ans = 0;
	for (i = 0; i < n; i++)
	{
		for (j = i; used[j] < 0; j = a[j])
			used[j] = i;
		if (used[j] == i)
			ans++;
	}
	printf("%d\n", ans);
	return 0;
}