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=[]
r=[]
for i in input().split():
  A.append(int(i))
#入力した配列をソート
A.sort()

#Queue操作
t=A.pop(-1) #最大値をとりだす
#print('t=',t)
b=A.pop(0)  #最小値をとりだす
#print('b=',b)

#残りの配列において
for i in A:
  #print(i)
  #非負の場合
  if i>=0:
    r.append([b,i]) #最小値と現在の値のペア
    b=b-i  #bを更新
  #負の場合
  else:
    r.append([t,i]) #最大値と現在の値のペア
    t=t-i #tを更新
print(t-b)
r.append([t,b])
for i in r:
  #print(i)
  print(i[0],i[1])