main :: IO ()
main = do

    input_line <- getLine
    let king = map read (words input_line) :: [Int]
    let kingx = king !! (0)
    let kingy = king !! (1)

    input_line2 <- getLine
    let destinaion = map read (words input_line2) :: [Int]
    let destinaionx = destinaion !! (0)
    let destinaiony = destinaion !! (1)
    


    


    
    putStrLn $ show (moving kingx kingy destinaionx destinaiony)
    return ()
    
moving :: Int -> Int -> Int -> Int -> Int
moving a b c d
    | a == b && c == d && a > c = a + 1
    | otherwise = max a b