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

ans_list = []
p = []
n = []

# 最大にプラス、最小にマイナスを割り当てる
p.append(A[-1])
n.append(A[0])

# 正ならプラスを負ならマイナスを割り当てる
for a in A[1:-1]:
    if a >= 0:
        p.append(a)
    elif a < 0:
        n.append(a)

# プラスが１つになるまで消す
while len(p) != 1:
    x = n.pop()
    y = p.pop()
    n.append(x-y)
    ans_list.append((x, y))

# マイナスがなくなるまで消す
while len(n) != 0:
    x = p.pop()
    y = n.pop()
    p.append(x-y)
    ans_list.append((x,y))

# 残ったものが最大値
M = p[0]
print(M)
for x, y in ans_list:
    print(x, y)