and height and drawn the two diagonals of the rectangle, forming four small triangles. He wishes to know the area of one of these triangles in the figure he has drawn.is drawing a logo for the next iteration of the KAIST contest. He has gotten lazy, so he has taken a rectangle of length
In tests worth 14 marks, .
The input will consist of two positive integers, and , on the first line and on the second.
Output, on a single line, the area of one of the given triangles. The area must be printed with exactly two digits after the decimal point.