module Main where
 
import Control.Monad
import System.Environment
 
-- 摂取したいカロリーに必要な炊く前の白米の重量を計算
calPerGram = (*) $ 1 / (2.2 * 1.68)
 
--
-- 値段と全重量、接種したいカロリーをひきすうにして、接種したいカロリーあたりの価格を計算
pricePerGram price amount targetCal = (price :: Double) /  times
  where
    amount' = amount * 1000
    times = amount' / calPerGram targetCal
 
 
 
 
main = do
  (p:a:t:_) <- getLine >>= return . map (read :: String -> Double) . words 
  print . round . pricePerGram p a $ t
 
 
 

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MzUwMCAxMCAzMDA=

3500 10 300