n = int(input())
A = [int(x)-1 for x in input().split()]

sign = 1

done = [0]*n

for i in range(n):
    if done[i]:
        continue
    now = i
    count = 0
    done[i] = 1
    while True:
        now = A[now]
        count += 1
        if now == i:
            break
        done[now] = 1
    if (count-1) % 2:
        sign *= -1

print(sign)