小群體

 n = int(input())

mapping = list(map(int,input().split()))

v = set()

cc = 0

for start in range(n):

  if start not in v:

    c = start

    while c not in v:

      v.add(c)

      c = mapping[c]

    cc += 1

print(cc)

# STDIN

# 5

# 1 2 0 4 3

# Output:

# 2