import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
public class Main {
	public static void main(String[] args) {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
				PrintWriter pw = new PrintWriter(System.out);) {
			String[] AB = br.readLine().split(" ");
			int A = Integer.parseInt(AB[0]);
			int B = Integer.parseInt(AB[1]);
			String[] S = br.readLine().split("-");
			if (S.length == AB.length && A - B == S[0].length() - S[1].length()) {
				pw.println("Yes");
			} else {
				pw.println("No");
			}
			pw.flush();
		} catch (Exception e) {
		}
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz