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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int n, cnt, f[111111], g[111111], h[111111], gg[111111];
int getf(int x) {
  if (x == g[x]) return x;
  g[x] = getf(g[x]);
  return g[x];
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &f[i]);
  for (int i = 1; i <= n; i++) g[i] = i, h[i] = 0;
  bool flag = true;
  for (int i = 1; i <= n; i++) {
    g[getf(i)] = getf(f[i]);
  }
  for (int i = 1; i <= n; i++)
    if (!gg[getf(i)]) gg[getf(i)] = ++cnt;
  for (int i = 1; i <= n; i++) {
    if (h[gg[getf(i)]] == 0)
      h[gg[getf(i)]] = f[i];
    else if (h[gg[getf(i)]] != f[i])
      flag = false;
  }
  if (!flag)
    printf("-1\n");
  else {
    printf("%d\n", cnt);
    for (int i = 1; i <= n; i++) printf("%d ", gg[getf(i)]);
    printf("\n");
    for (int i = 1; i <= cnt; i++) printf("%d ", h[i]);
    printf("\n");
  }
  return 0;
}