--import Control.Applicative ((<$>))
import Control.Monad (replicateM)
import Data.Char (isSpace)
import Data.List (transpose, unfoldr)
import qualified Data.ByteString.Char8 as BSC8


getLL :: (BSC8.ByteString -> [Integer]) -> IO [Integer]
getLL f = f <$> BSC8.getLine

readILL :: (BSC8.ByteString -> Maybe (Integer, BSC8.ByteString)) -> (BSC8.ByteString -> [Integer])
readILL f = unfoldr g
    where
        g s = do
            (n, s') <- f s
            return (n, BSC8.dropWhile isSpace s')

main :: IO ()
main = do
    [t, a, b] <- getLL (readILL BSC8.readInteger)
    print $ solve t a b

solve :: Integer -> Integer -> Integer -> Integer
solve t a b = (t `div` a) + 1 + (t `div` b) + 1 - (t `div` (lcm a b) + 1)