human
What is a Python program to find a positive integer m, and two functions g: [n] → [m], h: [m] → [n], such that g(h(x)) = x for all , and h(g(x)) = f(x) for all , or determine that finding these is impossible given the following:
Artsem has a friend Saunders from University of Chicago. Saunders presented him with the following problem.

Let [n] denote the set {1, ..., n}. We will also write f: [x] → [y] when a function f is defined in integer points 1, ..., x, and all its values are integers from 1 to y.

Now then, you are given a function f: [n] → [n]. Your task is to find a positive integer m, and two functions g: [n] → [m], h: [m] → [n], such that g(h(x)) = x for all , and h(g(x)) = f(x) for all , or determine that finding these is impossible.

Input

The first line contains an integer n (1 ≤ n ≤ 105).

The second line contains n space-separated integers — values f(1), ..., f(n) (1 ≤ f(i) ≤ n).

Output

If there is no answer, print one integer -1.

Otherwise, on the first line print the number m (1 ≤ m ≤ 106). On the second line print n numbers g(1), ..., g(n). On the third line print m numbers h(1), ..., h(m).

If there are several correct answers, you may output any of them. It is guaranteed that if a valid answer exists, then there is an answer satisfying the above restrictions.

Examples

Input

3
1 2 3

Output

3
1 2 3
1 2 3

Input

3
2 2 2

Output

1
1 1 1
2

Input

2
2 1

Output

-1
Solve the task in PYTHON3.
assistant
#Here is Python program to find a positive integer m, and two functions g: [n] → [m], h: [m] → [n], such that g(h(x)) = x for all , and h(g(x)) = f(x) for all , or determine that finding these is impossible.

n = int(input())
f = [None] + list(map(int, input().split(' ')))
invalid = False

g = [None] + [0] * n
h = [None]
x_is_f_which = [None] + [0] * n
m = 0
vis = [None] + [False] * n

for i in range(1, n + 1):
    x = f[i]
    if f[x] != x:
        invalid = True
        break
    if not vis[x]:
        vis[x] = True
        m = m + 1
        h.append(x)
        x_is_f_which[x] = m

if invalid:
    print('-1')
else:
    for i in range(1, n + 1):
        g[i] = x_is_f_which[f[i]]
    print(m)
    def print_list(l):
        print(' '.join(list(map(str, l[1:]))))
    print_list(g)
    print_list(h)