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
rr = raw_input
rrm = lambda: map(int, rr().split())

from collections import deque
def solve(N, A):
    S = sum(A)
    A.sort()
    A = deque(A)
    moves = []

    if A[0] > 0: # all pos, ans is S - A[0]
        ans = S - A[0]
        x = A.popleft()
        while len(A) >= 2:
            y = A.popleft()
            moves.append([x,y])
            x = x-y
        moves.append([A.pop(), x])
    elif A[-1] < 0:  # all neg, ans is -S + A[-1]
        ans = A[-1] - S
        x = A.pop()
        while A:
            y = A.pop()
            moves.append([x,y])
            x-=y
    else:
        pos = A.pop()
        neg = A.popleft()
        # neg soaks all pos
        while A and A[-1] >= 0:
            x = A.pop()
            moves.append([neg, x])
            neg -= x
        while A and A[0] <= 0:
            x = A.pop()
            moves.append([pos, x])
            pos -= x
        moves.append([pos, neg])
    return moves

N = int(rr())
A = rrm()
moves = solve(N, A)
ans = moves[-1][0] - moves[-1][1]
print ans
for row in moves:
    print " ".join(map(str, row))
    
