import Control.Applicative ((<$>))
import Data.List

main :: IO ()
main = solve <$> map read . words <$> getLine >>= putStrLn

solve :: [Int] -> String
solve [n, g, v] = let gv = n `div` 5 * g
                      (q, r) = gv `divMod` v
                  in show q ++ "." ++ concatMap show (take 13 $ unfoldr f r)
  where
    f x = let y = x * 10 in Just (y `divMod` v)