import sys

lines = sys.stdin.read().split('\n')

for i in range(len(lines) // 2):
	count = int(lines[i*2])
	monsters = [int(x) - 1 for x in lines[i*2+1].split(' ')]
	steps = 0

	locations = [None] * count

	for i in range(count):
		locations[monsters[i]] = i

	for i in range(count):
		if monsters[i] != i:
			m1 = monsters[i]

			monsters[i] = i
			monsters[locations[i]] = m1

			locations[m1] = locations[i]
			locations[i] = i

			steps += 1

	print(steps)
	#print(sum([1 if monster != (i+1) else 0 for i, monster in enumerate(monsters)]) / 2)