main = do
  (a:b:xs) <- map read . words <$> getLine
  s <- getLine
  putStrLn $ if solve s then "Yes" else "No"

solve a b s = and (map isNum (take a s)) && (head $ drop a s) == '-' && (map isNum ((drop (a+1) s))

isNum c = c `elem` ['0'..'9']