import java.util.*;

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 && s.charAt(i) != '-') {
        System.out.println("No");
        return;
      } else if (i != a && s.charAt(i) == '-') {
        System.out.println("No");
        return;
      }
    }

    System.out.println("Yes");


  }

}
