n = int(input())
friends_array = list(map(int, input().split()))
marked = [False] * n
counter = 0

for i in range(n):
    if not marked[i]:
        # 追蹤整個朋友圈，標記所有相關的人
        current = i
        while not marked[current]:
            marked[current] = True
            current = friends_array[current]
        counter += 1

print(counter)