Problem: 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 <image>, and h(g(x)) = f(x) for all <image>, 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

Solution (in PYTHON3):

Solution:
n = int(input())
f = [-1] + list(map(int, input().split()))
g = [-1]*(n+1)
h = [-1]
c = 1
for i in range(1, n+1):
	if(f[i] == i):
		g[i] = c
		h += [i]
		c += 1

hinv = {}
m = len(h)-1
for i in range(1, m+1):
	hinv[h[i]] = i

for i in range(1, n+1):
	if(g[i] == -1):
		try:
			g[i] = hinv[f[i]]
		except:
			print(-1)
			exit()
print(m)
print(*g[1:])
print(*h[1:])