main :: IO ()
main = do
  abcd <- map read . words <$> getLine
  putStrLn  $ show $ solve abcd

solve :: [Int] -> Int
solve [a, b, c, d] =
  minimum [a, meatLim, maxLim]
  where
    meatLim = b `div` c
    maxLim = d `div` (c + 1)