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
n,*a=map(int,open(0).read().split())

plus=[]
minus=[]
for aa in a:
    if aa>=0:
        plus.append(aa)
    else:
        minus.append(aa)

if len(plus)==n:
    plus.sort(reverse=True)
    minus.append(plus.pop())
elif len(minus)==n:
    minus.sort()
    plus.append(minus.pop())

print(sum(plus)-sum(minus))

xy=minus[0]
for i in range(len(plus)-1):
    print('{} {}'.format(xy,plus[i]))
    xy-=plus[i]

print('{} {}'.format(plus[-1],xy))
xy=plus[-1]-xy

for i in range(1,len(minus)):
    print('{} {}'.format(xy,minus[i]))
    xy-=minus[i]

