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 = 1e6 + 5;
map<int, int> id, mp;
int a[maxn], g[maxn], h[maxn];
int main() {
  int n;
  scanf("%d", &n);
  int tot = 0;
  id.clear();
  mp.clear();
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    if (mp[a[i]] == 0) {
      mp[a[i]] = ++tot;
      h[tot] = a[i];
    } else
      id[i] = mp[a[i]];
  }
  for (int i = 1; i <= n; i++) g[i] = mp[a[i]];
  bool flag = true;
  for (int i = 1; i <= tot; i++) {
    if (g[h[i]] != i) {
      flag = false;
      break;
    }
  }
  if (!flag)
    puts("-1");
  else {
    printf("%d\n", tot);
    for (int i = 1; i <= n; i++) printf("%d%c", g[i], i != n ? ' ' : '\n');
    for (int i = 1; i <= tot; i++) printf("%d%c", h[i], i != tot ? ' ' : '\n');
  }
  return 0;
}