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
N = int(input())
A = sorted(list(map(int, input().split())))
if N == 2:
    x, y = A[1], A[0]
    print(x-y)
    print(x, y)
    exit()
idx = bisect.bisect_left(A, 0)
if idx:
    if idx < N:
        Q = A[:idx]
        P = A[idx:]
    else:
        Q = A[:-1]
        P = [A[-1]]
else:
    Q = [A[0]]
    P = A[1:]


XY = []
LP = len(P)
for i in range(LP-1):
    XY.append((Q[0], P[i]))
    Q[0] -= P[i]
LQ = len(Q)
for i in range(LQ):
    XY.append((P[-1], Q[i]))
    P[-1] = P[-1] - Q[i]
ans = P[-1]
print(ans)
for x, y in XY:
    print(x, y)



