|A cat and a rabbit are playing a simple number guessing game.
The cat chose two different positive integers X and Y.
He then told the rabbit several numbers.
One of those numbers was X + Y and another was X - Y.
The others were simply made up.
The rabbit thinks the cat prefers large numbers. Given a int hints containing the numbers the cat told the rabbit, return the largest possible value of X * Y.
|-||hints will contain between 2 and 50 elements, inclusive.|
|-||Each element of hints will be between 1 and 100, inclusive.|
|-||All elements of hints will be distinct.|
|-||There will exist at least one pair of positive integers (X, Y) such that both X + Y and X - Y are elements of hints.|