import           Data.Char

main :: IO ()
main = do
    [a, b] <- map read . words <$> getLine :: IO [Int]
    s <- getLine
    putStrLn $ if f s a
                  && solve (take a s) (drop (a+1) s)
                  then "Yes"
                  else "No"
    where
      f = ((== '-') .) . (!!)

solve = flip ((.).(&&). p) p
    where
      p = all isDigit
