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()

def answer():
    p = sum(1 for i in a if i < 0)
    q = sum(1 for i in a if i >= 0)

    if p == 0:
        p += 1
        q -= 1
    if q == 0:
        p -= 1
        q += 1

    list_xy = []
    for i in range(q - 1):
        list_xy.append((a[0], a[p + i]))
        a[0] -= a[p + i]
    for i in range(p):
        list_xy.append((a[-1], a[i]))
        a[-1] -= a[i]
    return a[-1], list_xy


m, list_xy = answer()

print(m)
for x, y in list_xy:
    print(x, y)
