-- yukicoder My Practice
-- author: Leonardone @ NEETSDKASU

main = putStrLn . solve . map read . words =<< getLine

solve [n, g, v] = ans where
    gareki_count = n `div` 5
    gareki_weight = g * gareki_count
    gareki_by_room = gareki_weight * (10 ^ 12) `div` v
    (upper, under) = divMod gareki_by_room (10 ^ 12)
    ans = show upper ++ "." ++ show under