N = int(input())
A = list(map(lambda x:int(x)-1, input().split()))
visited = [-1] * N
ret = 0

for i in range(N):
	if visited[i] != -1:
		continue
	
	visited[i] = i
	
	if A[i] == i:
		ret += 1
		continue

	j = i

	while visited[A[j]] == -1:
		visited[A[j]] = i
		j = A[j]
		
	if visited[A[j]] == i:
		ret += 1
		
		
print(ret)