readInt :: S8.ByteString -> Maybe Integer
readInt bs =
    case S8.readInteger bs of
        Just (i, "") -> Just i
        _ -> Nothing
readInt :: S8.ByteString -> Maybe Integer
readInt bs =
    case S8.readInteger bs of
        Just (i, "") -> Just i
        _ -> Nothing
readInt bs =
    case S8.readInteger bs of
        Just (i, "") -> Just i
        _ -> Nothing