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()))
b=[i for i in a if i>=0]
c=[i for i in a if i<0]
if len(b)==n:
    b.sort()
    print(-b[0]+sum(b[1:]))
    now=b[0]
    for i in range(1,n-1):
        print(now,b[i])
        now-=b[i]
    print(b[-1],now)
elif len(c)==n:
    c.sort(reverse=1)
    print(c[0]-sum(c[1:]))
    now=c[0]
    for i in range(1,n):
        print(now,c[i])
        now-=c[i]
else:
    print(sum(b)-sum(c))
    for i in range(len(b)-1):
        print(c[0],b[i])
        c[0]-=b[i]
    for i in c:
        print(b[-1],i)
        b[-1]-=i