solve :: Integral a => a -> a -> a -> a -> a
solve n a b c = a1 + b1 + c1 - ab - bc - ca + abc
    where
        a1 = div n a
        b1 = div n b
        c1 = div n c
        ab = div n $ lcm a b
        bc = div n $ lcm b c
        ca = div n $ lcm c a
        abc = div n $ lcm a $ lcm b c

main :: IO ()
main = print . (\(n : a : b : c : _) -> solve n a b c) . map read . words =<< getContents