import Control.Monad
import Control.Applicative
import Data.List

main :: IO ()
main = do
    [a, b] <- fmap read . words <$> getLine :: IO [Int]
    case (a + b, a * b) of
        (15, _) -> putStrLn "+"
        (_, 15) -> putStrLn "*"
        _       -> putStrLn "x"