import Control.Monad
import Control.Applicative
import Data.List

main = do
  xs <- map read . lines <$> getContents :: IO [Double]
  mapM_ print $ solve xs

solve :: [Double] -> [Int]
solve = map flr

flr :: Double -> Int
flr v = ceiling $ 0.98 * (v / 9.8) ^ 2 + 1