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
# -*- coding: utf-8 -*-

def readInts():
  return [int(s) for s in input().split(" ")]

def main():
  N = readInts()[0]
  A = readInts()

  A.sort()
  numMinus = 1
  for i in range(1, N):
    if A[i] < 0:
      numMinus += 1
    else:
      break

  if numMinus == N:
    numMinus = N - 1

  seq = []
  for i in range(numMinus, N-1):
    seq.append((A[0], A[i]))
    A[0] = A[0] - A[i]
  for i in range(numMinus):
    seq.append((A[N-1], A[i]))
    A[N-1] = A[N-1] - A[i]

  print(A[N-1])
  for x, y in seq:
    print("{} {}".format(x, y))

if __name__ == "__main__":
  main()
