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)