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
import sys
from bisect import bisect_left

input = sys.stdin.readline


def main():
    N = int(input())
    A = list(map(int, input().split()))

    A.sort()
    idx = bisect_left(A[1:-1], 0)
    m_group = A[1:1 + idx]
    p_group = A[1 + idx: -1]

    ans = []

    MAX = A[-1]
    for m in m_group:
        ans.append(f"{MAX} {m}")
        MAX -= m

    MIN = A[0]
    for p in p_group:
        ans.append(f"{MIN} {p}")
        MIN -= p

    ans.append(f"{MAX} {MIN}")
    M = MAX - MIN

    print(M)
    print("\n".join(ans))


if __name__ == "__main__":
    main()
