--compatability
compatibility :: String -> String -> String
compatibility a b =
    a ++ (reaction (overlay 1 (removelikechars a b))) ++ b ++ " and " ++ b ++ (reaction (overlay 1 (removelikechars b a))) ++ a
        where
            reaction :: String -> String
            reaction [] = []
            reaction a
                | drop (length a - 1) a == "l" = " loves "
                | drop (length a - 1) a == "p" = " is physically attracted to "
                | drop (length a - 1) a == "h" = " hates "
                | drop (length a - 1) a == "i" = " is indifferent to "
                | otherwise = "ERROR"
            overlay :: Int -> String -> String
            overlay _ [] = []
            overlay n (x:xs)
                | n == 1 = ("l" ++ overlay 2 xs)
                | n == 2 = ("p" ++ overlay 3 xs)
                | n == 3 = ("h" ++ overlay 4 xs)
                | n == 4 = ("i" ++ overlay 1 xs)
                | otherwise = "ERROR"
            removelikechars :: String -> String -> String
            removelikechars [] _ = []
            removelikechars a b =
                if ((length [y | y <- b, [y] == (take 1 a)]) > 0)
                    then
                        removelikechars (drop 1 a) b
                    else
                        (take 1 a) ++ removelikechars (drop 1 a) b