-- yukicoder My Practice -- author: Leonardone @ NEETSDKASU main = putStrLn . solve . map read . words =<< getLine solve [n, g, v] = ans where bias = 10 ^ 12 gareki_count = n `div` 5 gareki_weight = g * gareki_count gareki_by_room = gareki_weight * bias `div` v (upper, under) = divMod gareki_by_room bias ans = show upper ++ "." ++ (tail $ show (under + bias))