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()) 
nums = list(map(int, input().split()))
nums.sort()

left = nums[0]
right = sum(nums[1:])

ans = right - left
arg = 0
for i in range(1, n - 1):
	left += nums[i]
	right -= nums[i]
	if right - left > ans:
		arg = i
		ans = right - left

print(ans)

l_list = nums[:(arg + 1)]
r_list = nums[(arg + 1):]

while len(l_list) > 1:
	x = r_list.pop()
	y = l_list.pop()
	print(str(x) + " " + str(y))
	r_list.append(x - y)

x = l_list.pop()
while len(r_list) > 1:
	y = r_list.pop()
	print(str(x) + " " + str(y))
	x = x - y

print(str(r_list.pop()) + " " + str(x))
