题目描述
Let N be a positive even number.
We have a permutation of (1, 2, ..., N), p = (p_1, p_2, ..., p_N). Snuke is constructing another permutation of (1, 2, ..., N), q, following the procedure below.
First, let q be an empty sequence. Then, perform the following operation until p becomes empty:
- Select two adjacent elements in p, and call them x and y in order. Remove x and y from p (reducing the length of p by 2), and insert x and y, preserving the original order, at the beginning of q.
When p becomes empty, q will be a permutation of (1, 2, ..., N).
Find the lexicographically smallest permutation that can be obtained as q.
Constraints
- N is an even number.
- 2 ≤ N ≤ 2 × 10^5
- p is a permutation of (1, 2, ..., N).
Input
Input is given from Standard Input in the following format:
N
p_1 p_2 ... p_N
Output
Print the lexicographically smallest permutation, with spaces in between.
Examples
Input
4
3 2 4 1
Output
3 1 2 4
Input
2
1 2
Output
1 2
Input
8
4 6 3 2 8 5 7 1
Output
3 1 2 7 4 6 8 5
输入格式
见题面
输出格式
见题面