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 bisect
N=int(input())
A=list(map(int,input().split()))
A.sort()
k=bisect.bisect_left(A,0)
a=-sum(A[:k])+sum(A[k:])
if N==2:
  a-=2*A[0]
elif k==0:
  a-=2*A[0]
elif k==N:
  a+=2*A[N-1]
print(a)
if N==2:
  print(A[1],A[0])
elif k>=N-1:
  x=A[N-1]
  for i in range(N-1):
    print(x,A[i])
    x-=A[i]
else:
  
    x=A[0]
    
    for i in range(max(k,1),N-1):
      print(x,A[i])
      x-=A[i]
    print(A[-1],x)
    x=A[-1]-x
    for i in range(1,k):
      print(x,A[i])
      x-=A[i]
  