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 bisect

def main():
	n = int(input())
	a = list(map(int,input().split()))
	a.sort()
	idx = bisect.bisect_left(a,0)
	if idx == 0:
		idx = 1
	elif idx == n:
		idx = -1
	cur_min = a[0]
	cur_max = a[-1]
	res = []
	for n in a[1:idx]:
		res.append('{} {}'.format(cur_max,n))
		cur_max -= n
	for n in a[idx:-1]:
		res.append('{} {}'.format(cur_min,n))
		cur_min -= n
	res.append('{} {}'.format(cur_max,cur_min))
	print(cur_max-cur_min)
	for r in res:
		print(r)

if __name__ == '__main__':
	main()