import Data.List

f::String->String
f [] ="Yes"
f (x:xs)=if not (x `elem` ['0'..'9']) then "No" else f xs

main = do
       e1<-getLine
       e2<-getLine
       let (a:b:[])=map read (words e1)::[Int]
       putStrLn $ if e2!!a=='-' then f (delete '-' e2) else "No"