import qualified Data.ByteString.Char8 as B
import Data.Maybe
import Data.Functor

primes :: Int -> Double -> [(Double, Int)]
primes n p = sieve (zip (replicate (n - 1) 1.0) [2..n])
  where
    sieve [] = []
    sieve ((l,x):xs) = (l,x):take (x - 1) xs ++ sieve (erase x (drop (x - 1) xs))
    erase y ((l, x):xs)
      | x `mod` y == 0 = ((1 - p) * l, x):erase y xs
      | otherwise = (l, x):erase y xs
    erase _ [] = []

main =
  do
    l <- words <$> getLine
    let n = read (l !! 0) :: Int
        p = read (l !! 1) :: Double
        k = primes n p
    (putStrLn . show) (foldl (\ r (v, _) -> v + r) 0.0 k)