import Data.Char
import Data.Bool

main = do
  [a,b] <- map read . words <$> getLine
  s <- getLine
  let
    (n1,s1) = splitAt a s
    (h,s2) = splitAt 1 s1
    (n2,s3) = splitAt b s2
  let ans = all isDigit n1 && h=="-" && all isDigit n2
  putStrLn $ bool "No" "Yes" ans