import Text.Printf (printf)

prob :: Double -> Double
prob n = 100 * (1 - p) * (1 - q) / (p * q + (1 - p) * (1 - q))
    where
        p = n / 10000
        q = 99 / 100

main :: IO ()
main = printf "%.14f\n" . prob =<< readLn