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
import sys
range = xrange
input = raw_input


n = int(input())
A = [int(x) for x in input().split()]

A.sort()

sign_stack = []
value_stack = [(A[n-1],A[0])]
numb = A[n-1] - A[0]
for i in reversed(range(1,n-1)):
    if A[i] >= 0:
        sign_stack.append(-1)
        numb = -numb
        value_stack.append((A[i], numb))
        numb = A[i] - numb
    else:
        sign_stack.append(1)
        value_stack.append((numb, A[i]))
        numb = numb - A[i]
sign_stack.append(1)

print numb
for sign,(x,y) in zip(sign_stack, value_stack):
    if sign>0:
        print x,y
    else:
        print y,x
