Problem A
Pizza Crust
                                             
      George has bought a pizza. George loves cheese. George thinks the pizza does not have enough cheese. George gets angry.
George’s pizza is round, and has a radius of $R$ cm. The outermost $C$ cm is crust, and does not have cheese. What percent of George’s pizza has cheese?
Input
The input consists of a single line with two space separated integers, $R$ and $C$.
Output
Output the percentage of the pizza that has cheese. Your answer must have an absolute or relative error of at most $10^{-6}$.
Limits
- 
        $1 \leq C \leq R \leq 100$ 
| Sample Input 1 | Sample Output 1 | 
|---|---|
| 1 1 | 0.000000000 | 
| Sample Input 2 | Sample Output 2 | 
|---|---|
| 2 1 | 25.000000 | 
