Problem Statement

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.

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.

Constraints

• N is an even number.
• 2 ≤ N ≤ 2 × 10^5
• p is a permutation of (1, 2, ..., N).

Sample Input 1

4
3 2 4 1

Sample Output 1

3 1 2 4

The solution above is obtained as follows:

p
q

(3, 2, 4, 1)
()

↓
↓

(3, 1)
(2, 4)

↓
↓

()
(3, 1, 2, 4)

Sample Input 2

2
1 2

Sample Output 2

1 2

Sample Input 3

8
4 6 3 2 8 5 7 1

Sample Output 3

3 1 2 7 4 6 8 5

The solution above is obtained as follows:

p
q

(4, 6, 3, 2, 8, 5, 7, 1)
()

↓
↓

(4, 6, 3, 2, 7, 1)
(8, 5)

↓
↓

(3, 2, 7, 1)
(4, 6, 8, 5)

↓
↓

(3, 1)
(2, 7, 4, 6, 8, 5)

↓
↓

()
(3, 1, 2, 7, 4, 6, 8, 5)

见题面 Input 部分

见题面 Output 部分