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
#!/usr/bin/env python

from collections import deque
import itertools as ite
import sys
import math

sys.setrecursionlimit(1000000)

INF = 10 ** 18
MOD = 10 ** 9 + 7

N = input()
A = map(int, raw_input().split())

pos1 = pos2 = 0
flag1 = flag2 = False
for i in range(N):
	if A[i] > 0:
		flag1 = True
		pos1 = i
	elif A[i] < 0:
		flag2 = True
		pos2 = i

if flag1 and flag2:
	print sum(abs(num) for num in A)
	n1 = A[pos1]
	n2 = A[pos2]
	for i in range(N):
		if i == pos1 or i == pos2:
			continue
		if A[i] > 0:
			print n2, A[i]
			n2 -= A[i]
		else:
			print n1, A[i]
			n1 -= A[i]
	print n1, n2
elif flag1:
	pos = 0
	for i in range(N):
		if A[pos] > A[i]:
			pos = i
	S = 0
	if pos == 0:
		S = 1
	n1 = A[pos]
	print sum(A) - n1 * 2
	for i in range(N):
		if i == pos or i == S:
			continue
		print n1, A[i]
		n1 -= A[i]
	print A[S], n1
else:
	pos = 0
	for i in range(N):
		if A[pos] < A[i]:
			pos = i
	n1 = A[pos]
	print -sum(A) + n1 * 2
	for i in range(N):
		if i == pos:
			continue
		print n1, A[i]
		n1 -= A[i]
		