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 = sorted(A)
plus = []
minus = []

for i in range(N):
    if i == 0:
        minus.append(A[i])
    elif i == N-1:
        plus.append(A[i])
    else:
        if A[i] > 0:
            plus.append(A[i])
        else:
            minus.append(A[i])

print(sum(plus)-sum(minus))
tmp = minus[0]
for i in range(len(plus)-1):
    print(tmp,plus[i])
    tmp -= plus[i]

minus[0] = tmp
tmp2 = plus[-1]
for i in range(len(minus)):
    print(tmp2,minus[i])
    tmp2 -= minus[i]
    

