import Control.Monad
import Control.Applicative
import Data.Functor
import Data.List
import Data.List.Split
import Data.Char

readInt = read :: String -> Int
getInt = readLn :: IO Int
getInts = map readInt . words <$> getLine
sjoin :: (Show a) => [a] -> String
sjoin = unwords . map show
cond :: a -> a -> Bool -> a
cond t f c = if c then t else f
-- end of templete

g  = 9.8 :: Double
height n = 5 * n - 5 :: Int
v x = sqrt $ 2 * g * x :: Double
vf = v . fromIntegral . height :: Int -> Double

f :: Double -> Int
f v0 = head . dropWhile ((<v0) . vf) $ [1..]

main = map read . lines <$> getContents >>= mapM_ (print . f)