import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		/*int M = sc.nextInt();
		System.out.println(24- M + 24);*/
		
		int a = sc.nextInt();
		int b = sc.nextInt();
		String s = sc.next();
		int length = s.length();
		if((a+b+1) != length) {
			System.out.println("NO");
			return;
		}else {
			char c = s.charAt(a);
			if(c != '-') {
				System.out.println("NO");
				return;
			}else {
				
				String[] str = s.split("-");
				if(str.length==2) {
					String A = str[0];
					String B = str[1];
					for(int i=0; i<a; i++) {
						char t = A.charAt(i);
						int tmp = Integer.valueOf(t);
						if(tmp<48 || tmp>57) {
							System.out.println("NO");
							return;
						}
					}
					for(int i=0; i<b; i++) {
						char t = B.charAt(i);
						int tmp = Integer.valueOf(t);
						if(tmp<48 || tmp>57) {
							System.out.println("NO");
							return;
						}
					}
					System.out.println("YES");
					return;
				}else {
					System.out.println("NO");
					return;
				}
			}
		}
		
	
	}
}
