Problem:
Score : 400 points

Problem Statement

Snuke has an empty sequence a.

He will perform N operations on this sequence.

In the i-th operation, he chooses an integer j satisfying 1 \leq j \leq i, and insert j at position j in a (the beginning is position 1).

You are given a sequence b of length N. Determine if it is possible that a is equal to b after N operations. If it is, show one possible sequence of operations that achieves it.

Constraints

All values in input are integers.

1 \leq N \leq 100

1 \leq b_i \leq N

Input

Input is given from Standard Input in the following format:

N
b_1 \dots b_N

Output

If there is no sequence of N operations after which a would be equal to b, print -1.
If there is, print N lines. In the i-th line, the integer chosen in the i-th operation should be printed. If there are multiple solutions, any of them is accepted.

Sample Input 1

3
1 2 1

Sample Output 1

1
1
2

In this sequence of operations, the sequence a changes as follows:

After the first operation: (1)

After the second operation: (1,1)

After the third operation: (1,2,1)

Sample Input 2

2
2 2

Sample Output 2

-1

2 cannot be inserted at the beginning of the sequence, so this is impossible.

Sample Input 3

9
1 1 1 2 2 1 2 3 2

Sample Output 3

1
2
2
3
1
2
2
1
1

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int N=sc.nextInt();
        int[] b = new int[N];
        for(int i=0;i<N;i++){
            b[i]=sc.nextInt();
        }
        int[] result=new int[N];

        for(int i=N-1;i>=0;i--){
            for(int j=i;j>=0;j--){
                if(b[j]==j+1){
                    result[i]=j+1;
                    for(int k=j;k<i;k++){
                        b[k]=b[k+1];
                    }
                    break;
                }
                if(j==0){
                    System.out.println(-1);
                    return;
                }
            }
        }
        for(int i=0;i<N;i++){

            System.out.println(result[i]);
        }


        System.out.println("test");
    }
}