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(map(int, input().split()))
a1=[i for i in a if i>=0]
a2=[i for i in a if i<0]
if a1 and a2:
    print(sum(a1)-sum(a2))
    mx,mn=a1[-1], a2[0]
    for i in a1[:-1]:
        print(mn,i)
        mn-=i
    for i in a2[1:]:
        print(mx,i)
        mx-=i
    print(mx,mn)
elif not a2:
    print(sum(a1[1:])-a1[0])
    mx,mn=a1[-1], a1[0]
    for i in a1[1:-1]:
        print(mn,i)
        mn-=i
    print(mx,mn)
else:
    print(a2[-1]-sum(a2[:-1]))
    mx,mn=a2[-1], a2[0]
    for i in a2[1:-1]:
        print(mx,i)
        mx-=i
    print(mx,mn)