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())
l=list(map(int,input().split()))
l.sort()
if l[0]>=0 :
  print(sum(l)-2*l[0])
  for i in range(1,n-1):
    print(l[0],l[i])
    l[0]-=l[i]
  print(l[-1],l[0])
elif l[-1]<0:
  print(abs(sum(l)-2*l[-1]))
  for i in range(n-1):
    print(l[-1],l[i])
    l[-1]-=l[i]
else:
  cnt=0
  i=0
  while l[i]<0:
    cnt+=1
    if l[i+1]>=0:
      break
    i+=1
  ans=0
  for j in range(n):
    ans+=abs(l[j])
  print(ans)
  for j in range(n-2-i):
    print(l[0],l[i+j+1])
    l[0]-=l[i+j+1]
  for j in range(i+1):
    print(l[-1],l[j])
    l[-1]-=l[j]
    
