There are two vector A(x1, x2, x3, ..., xn) and B(y1, y2, ..., yn), and the dot product(点积) is x1*y1 + x2*y2 + ... + xn*yn.
You can swap the order of any dimension, for example, A = {1, 2, 3}, then you can make A to {1, 3, 2} or {2, 1, 3} and so on.
Now you need to calculate the maximum value of dot product.
For each test case, print the maximum value of dot product.