import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		boolean ans = true;
		String s = sc.next();
		char c[] = s.toCharArray();
		for (int i = 0; i <= s.length() - 1; i++) {
			if (i == a && c[i] != '-') {
				ans = false;

			}



		}
		if (s.length() != a + b + 1) {
			ans = false;
		}

		if (ans) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
}