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 main() {
  int n;
  cin >> n;
  int A[n + 1];
  for (int i = 1; i <= n; i++) {
    cin >> A[i];
  }
  map<int, int> G, H, P;
  int C[n + 1];
  for (int i = 1; i <= n; i++) {
    C[i] = 0;
  }
  int m = 0;
  int ans = 1;
  for (int i = 1; i <= n; i++) {
    if (i != A[i]) {
      if (C[A[i]] != 0) {
        ans = 0;
        break;
      }
      C[i] = 1;
    }
    if (P[A[i]]) {
      G[i] = P[A[i]];
      H[P[A[i]]] = A[i];
    } else {
      m++;
      P[A[i]] = m;
      G[i] = P[A[i]];
      H[P[A[i]]] = A[i];
    }
  }
  if (ans == 0) {
    cout << -1 << endl;
  } else {
    cout << m << endl;
    for (int i = 1; i <= n; i++) {
      cout << G[i] << ' ';
    }
    cout << endl;
    for (int i = 1; i <= m; i++) {
      cout << H[i] << ' ';
    }
    cout << endl;
  }
  return 0;
}