Poly-Circle
Problem
Given a regular polygon of N sides with side length a. The task is to find the area of the Circle which inscribed in the polygon with no fractional part. If an incorrect combination of N and a are given print -1.
In the first line input will contain N and a separated by space.
Input
6 4
Output
37
Time Limit: 5
Memory Limit: 256
Source Limit:
