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

namespace atcorder2
{
    class Program
    {
        public static long Read()
        {
            return long.Parse(Console.ReadLine());
        }

        public static long[] Reads()
        {

            return Console.ReadLine().Split().Select(long.Parse).ToArray();
        }

       




        static void Main(string[] args)
        {
            var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);


            var ab = Reads();
            var a = ab[0];
            var b = ab[1];
            var s = Console.ReadLine();
            var ans = "Yes";
            for (int i = 0; i < s.Length; i++)
            {
                bool f = false;
                if (i != a && '0' <= s[i] && s[i] <= '9') f = true;
                else if (s[i] == '-') f = true;

                if (!f) ans = "No";
            }
            Console.WriteLine(ans);


            Console.Out.Flush();
        }
    }
}


