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();
    String s = sc.next();

    for (int i = 0; i < s.length(); i++) {
      if (i == a) {
        if (s.charAt(i) != '-') {
          System.out.println("No");
          return;
        }
      } else {
        if (s.charAt(i) == '-') {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  }
}