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=[int(i) for i in input().split()]
if min(A)>=0:
  A.sort()
  print(sum(A)-2*A[0])
  k=A[0]
  for i in range(1,N-1):
    print(k,A[i])
    k-=A[i]
  print(A[N-1],k)
  exit()
if max(A)<=0:
  A.sort()
  print(-sum(A)+2*A[N-1])
  k=A[N-1]
  for i in range(1,N-1)[::-1]:
    print(k,A[i])
    k-=A[i]
  print(k,A[0])
  exit()
A.sort()
A_=list(map(abs,A))
print(sum(A_))
for i in range(1,N-1):
  if A[i]<0:
    print(A[N-1],A[i])
    A[N-1]-=A[i]
  else:
    print(A[0],A[i])
    A[0]-=A[i]
print(A[N-1],A[0])

    

