object Main extends App {
	val ab = scala.io.StdIn.readLine.split(" ").map(_.toInt)
	val s = scala.io.StdIn.readLine.toList

	var flag = true
	var temp1 = ab(0)
	var temp2 = ab(1)

	for(i<-s){
		if(i != '-' && flag) temp1 = temp1 - 1
		else if(i != '-' && ! flag) temp2 = temp2 - 1
		else flag = false
	}

	if(temp1 == 0 && temp2 == 0)  println("Yes")
	else println("No")

}
