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

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

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

