import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;




public class Main {

    public static void main(String[] args) {

    	Main main=new Main();

    	main.run();

    }

    void run() {
    	Scanner sc=new Scanner(System.in);
    
    	int A=sc.nextInt();
    	int B=sc.nextInt();
    	
    	String str=sc.next();
    	String[] S=str.split("");
    	
    	if(S[A].equals("-")) {
    		
    		int length=str.length();
    		int lengthnum=str.replaceAll("-","").length();
    		
    		int diff=length-lengthnum;
    		
    		if(diff==1) {
    			System.out.println("Yes");
    		}else {
    			System.out.println("No");
    		}
    		
    	}
    }


}

