def swap(list, pos1, pos2):
	tmp = list[pos1]
	list[pos1] = list[pos2]
	list[pos2] = tmp
	return list

def solve(nums):

	changed = True;
	changes = 0;

	while changed:
		changed = False;
		for i, num in enumerate(nums):
			if i != num:	
				nums = swap(nums, i, num)
				changed = True; 
				changes = changes + 1

	print(changes)
loop = True

while loop:
	
	try:
		N = int(input(""))
		nums = []

		line = input("")
		strlist = line.split(" ")

		for i in strlist:
			nums.append(int(i) - 1) 

		solve(nums)
	except:
		loop = False