Question
Quad Frame
Kael possesses M rods, each with length Bi for the ith rod. He aims to select any 4 rods to construct a rectangle. Determine the maximum possible area of such a rectangle. If no rectangle can be formed, output 0.
Input
The first line of the input contains a single integer M.
The second line of the input contains M space-separated integers, the lengths of the rods.
The second line of the input contains M space-separated integers, the lengths of the rods.
Output
Print the maximum possible area of a rectangle that can be formed using the given rods. If no such rectangle can be formed, print 0.
Example
Sample Input
6
3 1 2 4 2 1
Sample Output
2
6
3 1 2 4 2 1
Sample Output
2