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;
const int INF = 1000000000;
const int dir_4[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
const int dir_8[8][2] = {{1, 0},  {1, 1},   {0, 1},  {-1, 1},
                         {-1, 0}, {-1, -1}, {0, -1}, {1, -1}};
int main() {
  static int n;
  static int f[100010];
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &f[i]);
  static int k = 1;
  static int g[100010], h[100010];
  for (int i = 1; i <= n; i++) {
    if (f[f[i]] != f[i]) {
      puts("-1");
      return 0;
    }
    if (f[i] == i) {
      g[i] = k;
      h[k] = i;
      k++;
    }
  }
  for (int i = 1; i <= n; i++) {
    g[i] = g[f[i]];
  }
  printf("%d\n", k - 1);
  for (int i = 1; i <= n; i++) {
    printf("%d%c", g[i], (i == n) ? '\n' : ' ');
  }
  for (int i = 1; i <= k - 1; i++) {
    printf("%d%c", h[i], (i == k - 1) ? '\n' : ' ');
  }
}