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 argc, char **argv) {
  int n;
  scanf("%d", &n);
  vector<int> f(n + 1, -1);
  vector<int> g(n + 1, -1);
  vector<int> h(1);
  int m = 0;
  vector<bool> b(n + 1, false);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &f[i]);
    if (f[i] == i) {
      m++;
      h.push_back(i);
      g[i] = m;
      b[i] = true;
    }
  }
  for (int i = 1; i <= n; i++) {
    if (f[i] != i) {
      int to = g[f[i]];
      if (b[f[i]] == false || to == -1) {
        puts("-1");
        return 0;
      }
      g[i] = to;
    }
  }
  printf("%d\n", m);
  for (int i = 1; i <= n; i++) {
    if (i > 1) {
      putchar(' ');
    }
    printf("%d", g[i]);
  }
  puts("");
  for (int i = 1; i <= m; i++) {
    if (i > 1) {
      putchar(' ');
    }
    printf("%d", h[i]);
  }
  puts("");
  return 0;
}