import Control.Applicative
import Control.Monad
import Data.List
import Data.Array
import Data.Char

main = do
  [a, b] <- map (read::String -> Int) . words <$> getLine
  s <- getLine
  let valid = snd $ foldl (\(index, isValid) c -> if (index == a && c == '-') || (index /= a && isDigit c) then (index + 1, isValid) else (index + 1, False)) (0, True) s
  putStrLn $ if valid then "Yes" else "No"


