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 = list(map(int, input().split()))

A.sort()
B = A[1:N-1]
amax=A[-1]
amin=A[0]

"""
a       p1
a-p1    p2
a-p1-p2 p3
として、
b a-sum(p)
で符号を入れ替え、
b-a+sum(p)    n1
b-a+sum(p)-n1 n2
とすると
b-a+sum(pos)-sum(neg)を実現できる。
bは全体で最大（Negの場合も）
aは全体で最小（Posの場合も）を選べばよい
"""
ANS = []
ind = N-2
wk = amin
while A[ind] >= 0 and ind >= 1:
  ANS.append((wk, A[ind]))
  wk -= A[ind]
  ind -= 1

ANS.append((amax, wk))
wk = amax - wk
while ind >= 1:
  ANS.append((wk, A[ind]))
  wk -= A[ind]
  ind -= 1

print(wk)
for a,b in ANS:
  print(a,b)
    