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;
using vi = vector<int>;
int main() {
  int n;
  scanf("%d", &n);
  vi f(n + 1);
  for (int i = 1; i <= n; ++i) scanf("%d", &f[i]);
  int m = 0;
  for (int i = 1; i <= n; i++)
    if (f[i] == i) m++;
  if (m == 0) {
    printf("-1\n");
    return 0;
  }
  vi h(m + 1);
  vi g(n + 1, -1);
  vi matched(n + 1, 0);
  int k = 1;
  for (int i = 1; i <= n; i++) {
    if (f[i] == i) {
      h[k] = i;
      g[i] = k;
      ++k;
      matched[i] = 1;
    }
  }
  for (int i = 1; i <= n; ++i) {
    if (f[i] != i) {
      int x = f[i];
      if (!matched[x]) {
        printf("-1\n");
        return 0;
      } else
        g[i] = g[x];
    }
  }
  printf("%d\n", m);
  printf("%d", g[1]);
  for (int i = 2; i <= n; i++) printf(" %d", g[i]);
  printf("\n%d", h[1]);
  for (int i = 2; i <= m; i++) printf(" %d", h[i]);
  printf("\n");
  return 0;
}