import Data.List.Split
import Data.Char

main :: IO ()
main = do
  [a,b] <- map read . words <$> getLine
  s <- getLine
  putStrLn $ if f s a b then "Yes" else "No"

f :: String -> Int -> Int -> Bool
f s a b
  | (head $ drop a s) /= '-' = False
  | not $ any (=='-') = False
  | (length $ filter (=='-') s) > 1 = False
  | otherwise  =
      all (&&True) $ concatMap (map isDigit . show) (splitOn "-" s)
