Kornislav the turtle never has anything interesting to do.
Since he’s going to live for three hundred years, he keeps
trying to find way to kill time. This weekend he started
playing "enclose the largest rectangle".
To start with, Kornislav needs four positive integers. He
tries to enclose a rectangle by moving in one direction, then
turning 90 degrees, then walking in the new direction etc.
Kornislav makes a total of three 90degree turns and walks four
segments.
When walking in some direction, the number of steps he takes
must be equal to one of the four chosen integers and each
integer must be used exactly once. Depending on the order in
which Kornislav uses the integers, his walk will make various
shapes, some of which don’t contain enclosed rectangles. Write
a program that calculates the largest rectangle the turtle can
enclose with its walk.
Input
The first line contains four positive integers $A, B, C$ and $D~ (0 < A, B, C, D < 100)$, the
four chosen integers.
Output
Output the largest area.
Sample Input 1 
Sample Output 1 
1 2 3 4

3

Sample Input 2 
Sample Output 2 
4 4 3 4

12
