using System;
using System.Collections.Generic;
using System.Linq;

namespace AtCoder
{
    internal static class Program
    {
        private static void Main()
        {
            int[] ab = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
            string text = Console.ReadLine();
            string res = "Yes";

            if (text.Length != ab[0] + ab[1] + 1)
                res = "No";
            
            for (int i = 0; i < ab[0]; i++)
                if (!char.IsDigit(text[i]))
                    res = "No";

            if (text[ab[0]] != '-')
                res = "No";

            for (int i = ab[0] + 1; i < ab[1]; i++)
                if (!char.IsDigit(text[i]))
                    res = "No";
            

            Console.WriteLine(res);
        }
    }
}