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()

if a[0]<=0 and a[-1]>=0:
    m = 0
    for i in range(n):
        m+=abs(a[i])
elif a[0]>0:
    m = sum(a)-a[0]*2
else:
    m = a[-1]
    for i in range(n-1):
        m+=abs(a[i])

print(m)

b = [a[0]] # -
c = [] # +

for i in range(1,n-1):
    if a[i]<0:
        b.append(a[i])
    else:
        c.append(a[i])

for x in c:
    print(b[-1],end=' ')
    print(x)
    b[-1]-=x
for y in b:
    print(a[-1],end=' ')
    print(y)
    a[-1]-=y

