n = int(input())
p = list(map(int, input().split()))
visited = [False] * n
total = 0

for i in range(n):
    if not visited[i]:
        if p[i] == i + 1:
            visited[i] = True
            continue
        cycle_length = 0
        current = i
        while not visited[current]:
            visited[current] = True
            cycle_length += 1
            current = p[current] - 1
        total += (cycle_length - 1)

print(total)