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 MAX_N = 100010;
int n;
int f[MAX_N], g[MAX_N], h[MAX_N];
int show[MAX_N];
int main() {
  while (~scanf("%d", &n)) {
    for (int i = 1; i <= n; ++i) scanf("%d", &f[i]);
    int flag = 0;
    for (int i = 1; i <= n; ++i) {
      if (f[i] != f[f[i]]) flag = 1;
    }
    if (flag)
      puts("-1");
    else {
      memset(show, -1, sizeof(show));
      int tot = 0;
      for (int i = 1; i <= n; ++i) {
        int& cur = show[f[i]];
        if (cur == -1) {
          cur = ++tot;
          h[tot] = f[i];
        }
        g[i] = cur;
      }
      printf("%d\n", tot);
      for (int i = 1; i <= n; ++i) printf("%d ", g[i]);
      puts("");
      for (int i = 1; i <= tot; ++i) printf("%d ", h[i]);
      puts("");
    }
  }
  return 0;
}