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)

ans = a[0]
ans_l = []
ans_e = a[-1]

if ans_e >= 0:
    for i in range(1,n-1):
        if a[i] < 0:
            ans_l += [(ans_e, a[i])]
            ans_e -= a[i]
        if a[i] >= 0:
            ans_l += [(ans, a[i])]
            ans -= a[i]

    ans_l += [(ans_e,ans)]
    ans = ans_e - ans

else:
    ans = ans_e
    for i in range(0,n-1):
        ans_l += [(ans, a[i])]
        ans -= a[i]

print(ans)

for x, y in ans_l:
    print(x,y)
