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

namespace ConsoleApp11
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] AB = Console.ReadLine().Split().Select(int.Parse).ToArray();
            string S = Console.ReadLine();
            string ans = "Yes";
            if (AB[0] + AB[1] + 1 == S.Length)
            {
                if (S[AB[0]] == '-')
                {
                    for (int i = 0; i < S.Length; i++)
                    {
                        switch (S[i])
                        {
                            case '0': break;
                            case '1': break;
                            case '2': break;
                            case '3': break;
                            case '4': break;
                            case '5': break;
                            case '6': break;
                            case '7': break;
                            case '8': break;
                            case '9': break;
                            default:ans = "No";
                                break;
                        }
                    }
                }
                else { ans = "No"; }
            }
            else { ans = "No"; }
            Console.WriteLine(ans);
        }
    }
}