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
#sys.stdin=open("data.txt")
input=sys.stdin.readline
mii=lambda:map(int,input().split())

n=int(input())

pos=[]
neg=[]
z=0

for i in mii():
    if i>=0: pos.append(i)
    else: neg.append(i)

if not pos:
    x=max(neg)
    neg.remove(x)
    pos.append(x)
if not neg:
    x=min(pos)
    pos.remove(x)
    neg.append(x)

merge=[]
while len(pos)>1:
    merge.append((neg[0],pos[-1]))
    neg[0]-=pos.pop(-1)
while len(neg)>0:
    merge.append((pos[0],neg[-1]))
    pos[0]-=neg.pop(-1)

print(pos[0])
for i,j in merge:
    print("%d %d"%(i,j))






