There are N integers, A_1, A_2, ..., A_N, written on a blackboard.

We will repeat the following operation N-1 times so that we have only one integer on the blackboard.

* Choose two integers x and y on the blackboard and erase these two integers. Then, write a new integer x-y.



Find the maximum possible value of the final integer on the blackboard and a sequence of operations that maximizes the final integer.

Constraints

* 2 \leq N \leq 10^5
* -10^4 \leq A_i \leq 10^4
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
A_1 A_2 ... A_N


Output

Print the maximum possible value M of the final integer on the blackboard, and a sequence of operations x_i, y_i that maximizes the final integer, in the format below.

Here x_i and y_i represent the integers x and y chosen in the i-th operation, respectively.

If there are multiple sequences of operations that maximize the final integer, any of them will be accepted.


M
x_1 y_1
:
x_{N-1} y_{N-1}

Output

Print the maximum possible value M of the final integer on the blackboard, and a sequence of operations x_i, y_i that maximizes the final integer, in the format below.

Here x_i and y_i represent the integers x and y chosen in the i-th operation, respectively.

If there are multiple sequences of operations that maximize the final integer, any of them will be accepted.


M
x_1 y_1
:
x_{N-1} y_{N-1}

Examples

Input

3
1 -1 2


Output

4
-1 1
2 -2


Input

3
1 1 1


Output

1
1 1
1 0
# -*- coding: utf-8 -*-
"""
Created on Sat Jun 15 20:54:34 2019

@author: Yamazaki Kenichi
"""

N = int(input()) 
A = list(map(int,input().split()))

A.sort()

for near0 in range(N):
    if A[near0] > 0:
        break

if near0 != 0:
    near0 -= 1

tmp = A[near0]
T = []
for i in range(near0+1,N-1):
    T.append([tmp,A[i]])
    tmp = tmp - A[i]

T.append([A[N-1],tmp])
tmp = A[N-1] - tmp
for i in range(near0):
    T.append([tmp,A[i]])
    tmp = tmp - A[i]

print(tmp)
for t in T:
    print(' '.join(map(str,t)))
