content: main :: IO () 
  main = do 
      putStrLn "Enter operation (+ or *):" 
      op <- getLine 
      putStrLn "Enter two numbers:" 
      num1 <- readLn 
      num2 <- readLn 
      let applyOp "+" = (+) 
          applyOp "*" = (*) 
          applyOp _   = error "Invalid operation"  -- Handle invalid input
      print (applyOp op num1 num2)
  