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
    sieve i arr
      | i >= (n `div` 2) = return arr
      | otherwise = erase (i * 2 - 1) >>= sieve (i + 1)
      where
        erase j
          | j >= (n `div` 2) = return arr
          | otherwise =
            readArray arr j >>= \ b ->
              writeArray arr j (p * b) >>
                erase (j + i - 1)

main =
  words <$> getLine >>= \ (f0:f1:_) ->
    let n = read f0 :: Int
        p = read f1 :: Double
    in (putStrLn . show) (foldr (+) 0 (elems (primes n p)))