import Control.Monad
import Data.List
import Data.Char
main=do
    [a,b]<-map read.words<$>getLine
    s<-getLine
    putStrLn $ chk 0 a b s
chk i a b []
    | i == (a+b+1) = "Yes"
    | True = "No"
chk i a b (s:ss)
    | i<a && isDigit s = chk (i+1) a b ss
    | i==a && s=='-' = chk (i+1) a b ss
    | i>a && isDigit s = chk (i+1) a b ss
    | True = "No"