iogetints :: IO [Int]
iogetints = do
  s <- getLine
  return $ map read $ words s

solve :: Int -> Int -> Char
solve a b
	| a + b == 15 = '+'
	| a * b == 15 = '*'
	| otherwise = 'x'

main :: IO ()
main = do 
	[a, b] <- iogetints
	putChar (solve a b)