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=int(input())
a=list(map(int,input().split()))
a.sort()

l,r=0,n-1
while r-l!=1:
  t=(l+r)//2
  if a[t]>0:
    r=t
  else:
    l=t
if r==n-1:
  print(-sum(a[:-1])+a[-1])
  t=a[-1]
  for i in a[:-1]:
    print(t,i)
    t-=i
else:
  print(-a[0]+sum(map(abs,a[1:-1]))+a[-1])
  for i in a[r:-1]:
    print(a[0],i)
    a[0]-=i
  for i in a[:r]:
    print(a[-1],i)
    a[-1]-=i
  
    