import Control.Monad import Control.Monad.ST import Data.Array.ST import Data.Array.Unboxed import Data.Functor import Debug.Trace primes :: Int -> Double -> UArray Int Double primes n p = runSTUArray (newArray (2, n) 1.0 >>= sieve 2) where invp = 1 - p sup = n sieve i arr | i > sup = return arr | otherwise = erase (i * 2) >>= sieve (i + 1) where erase j | j > sup = return arr | otherwise = readArray arr j >>= \ b -> writeArray arr j (invp * b) >> erase (j + i) main = words <$> getLine >>= \ (f0:f1:_) -> let n = read f0 :: Int p = read f1 :: Double in (putStrLn . show) (foldr (+) 0 (elems (primes n p)))