import Data.List

main = do
  one <- getLine
  str <- getLine
  let x = read . head . words $ one :: Int
  putStrLn $ main' x str

main' :: Int -> String -> String
main' x cs
  | cs!!x == '-'
    && length (delete '-' cs) == length cs - 1
    && all (\x -> x `elem` ['0'..'9']) (delete '-' cs) = "Yes"
  | otherwise