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()))
m,p=[],[]
for i in A:
    if i>=0:
        p.append(i)
    else:
        m.append(i)
if m and p:
    print(sum(p)-sum(m))
    t=m[0]
    for i in p[:-1]:
        print(t,i)
        t-=i
    print(p[-1],t)
    t=p[-1]-t
    for i in m[1:]:
        print(t,i)
        t-=i
elif p:
    p.sort()
    print(sum(p[1:])-p[0])
    t=p[0]
    for i in p[1:-1]:
        print(t,i)
        t-=i
    print(p[-1],t)
else:
    m.sort(reverse=1)
    print(m[0]-sum(m[1:]))
    t=m[0]
    for i in m[1:]:
        print(t,i)
        t-=i