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()
l=[]
sum=-a[0]+a[n-1]
for i in range(n-2):
    sum+=abs(a[i+1])
print(sum)

x=a[n-1]-a[0]
for i in range(n-1):
    if i==0:
        l.append([a[n-1],a[0]])
    else:
        if a[i]<0:
            l.append([x,a[i]])
            x+=abs(a[i])
        else:
            s=l[i-1][0]
            t=l[i-1][1]
            l[i-1][0]=t
            l[i-1][1]=s
            l.append([a[i],-x])
            x+=a[i]

for y in l:
    print(y[0],y[1])