using System;

namespace ABC084_B_Postal_Code
{
	internal class Program
	{
		public static void Main(string[] args)
		{
			string[] input = Console.ReadLine().Split(' ');
			int a = int.Parse(input[0]);
			int b = int.Parse(input[1]);
			string s = Console.ReadLine();

			int hihunCount = 0;
			for (int i = 0; i < s.Length; i++)
			{
				if (s.Substring(i, 1) == "-") hihunCount++;
			}

			if (hihunCount > 1)
			{
				Console.WriteLine("No");
				return;
			}

			for (int i = 0; i < s.Length; i++)
			{
				int beforeStrLen = s.Substring(0, i).Length;
				int afterStrLen = s.Substring(i + 1, s.Length - (i + 1)).Length;
				if (s.Substring(i, 1) == "-" && s.Length == a + b + 1)
				{
					if (beforeStrLen <= 9 && afterStrLen <= 9)
					{
						Console.WriteLine("Yes");
						return;
					}
				}
			}
			
			Console.WriteLine("No");
		}
	}
}