import Control.Applicative ((<$>))
import Data.List (unfoldr)
import Data.Set (Set)
import qualified Data.Set as S
import Data.Char (isSpace)
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B

readIntList :: IO [Int]
readIntList = unfoldr f <$> B.getLine
    where
        f s = do
            (n, s') <- B.readInt s
            return (n, B.dropWhile isSpace s')

main :: IO ()
main = print =<< solve <$> readIntList

solve :: [Int] -> Int
solve [a, b] = S.size s
    where
        s = S.difference (S.fromDistinctAscList [23..25]) (S.fromDistinctAscList [a..b])