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 MAXN = 1e5 + 5;
int n, m;
int f[MAXN];
int g[MAXN];
int h[MAXN];
bool used[MAXN];
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> f[i];
    if (!used[f[i]]) m++;
    used[f[i]] = 1;
  }
  for (int i = 1; i <= n; i++) {
    g[i] = -1;
  }
  int cur = 1;
  for (int i = 1; i <= n; i++) {
    if (g[f[i]] == -1) {
      g[i] = cur;
      g[f[i]] = cur;
      cur++;
    } else {
      g[i] = g[f[i]];
    }
  }
  for (int i = 1; i <= n; i++) {
    h[g[i]] = f[i];
  }
  for (int i = 1; i <= n; i++) {
    if ((g[i] < 1) || g[i] > m) {
      cout << "-1\n";
      return 0;
    }
    if (h[g[i]] != f[i]) {
      cout << "-1\n";
      return 0;
    }
  }
  for (int i = 1; i <= m; i++) {
    if ((h[i] < 1) || (h[i] > n)) {
      cout << "-1\n";
      return 0;
    }
    if (g[h[i]] != i) {
      cout << "-1\n";
      return 0;
    }
  }
  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;
}