-- no.212 TLE になります＞＜
import Text.Printf
main = do
    line <- getLine
    printf "%f\n" $ no212 $ map read $ words line

no212 :: [Integer] -> Double
no212 [p, c] = (fromIntegral $ gokei [p, c]) /
        (fromIntegral $ (fromIntegral $ length sosuSai) ^ p * (fromIntegral $  length gosuSai) ^ c)
no212 _ = 0

sosuSai = [2, 3, 5, 7, 11, 13] :: [Integer]
gosuSai = [4, 6, 8, 9, 10, 12] :: [Integer]

gokei :: [Integer] -> Integer
gokei [0, 0] = 1
gokei [p, 0] = sum [x * gokei [p - 1, 0] | x <- sosuSai]
gokei [p, c] = sum [y * gokei [p, c - 1] | y <- gosuSai]
gokei _ = 0