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())
ps = []
mis = []
for _ in input().split():
  item = int(_)
  if item >= 0:
    ps.append(item)
  else:
    mis.append(item)
  
mis.sort(reverse = True)
ps.sort()
if len(mis) == 0:
  mis = [ps[0]]
  ps = ps[1:]
if len(ps) == 0:
  ps = [mis[0]]
  mis = mis[1:]
print(sum(ps) - sum(mis))

pre = mis[0]
for p in ps[:len(ps) - 1]:
  print(pre, p)
  pre -= p
print(ps[-1], pre)
pre = ps[-1] - pre
for m in mis[1:]:
  print(pre, m)
  pre -= m


