Problem B
Pizza Crust

Photo by cyclonebill.

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

• $1\le C\le R\le 100$

1 1

0.000000000

2 1

25.000000