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

def solve():
    N = int(raw_input())
    A = [int(_) for _ in raw_input().split()]
    A.sort()
    ret = abs(A[N-1] - A[0])
    rever = [0] * (N - 1)
    for i in range(1, N-1):
        if A[i] >= 0:
            ret = ret + A[i]
            rever[i-1] = 1
        else:
            ret = ret - A[i]
    print ret
    def PrintAndCalcSave(a, b, rever):
        if rever == 0:
            print a, b
            return a - b
        else:
            print b, a
            return b - a

    cnt = 0
    if A[N-1] > A[0]:
        save = PrintAndCalcSave(A[N-1], A[0], rever[cnt])
    else:
        save = PrintAndCalcSave(A[0], A[N-1], rever[cnt])
    cnt += 1
    for i in range(1, N - 1):
        if A[i] >= 0:
            save = PrintAndCalcSave(A[i], save, rever[cnt])
        else:
            save = PrintAndCalcSave(save, A[i], rever[cnt])
        cnt += 1

if __name__ == '__main__':
    solve()
