Problem:
Score : 200 points

Problem Statement

The postal code in Atcoder Kingdom is A+B+1 characters long, its (A+1)-th character is a hyphen -, and the other characters are digits from 0 through 9.

You are given a string S. Determine whether it follows the postal code format in Atcoder Kingdom.

Constraints

1≤A,B≤5

|S|=A+B+1

S consists of - and digits from 0 through 9.

Input

Input is given from Standard Input in the following format:

A B
S

Output

Print Yes if S follows the postal code format in AtCoder Kingdom; print No otherwise.

Sample Input 1

3 4
269-6650

Sample Output 1

Yes

The (A+1)-th character of S is -, and the other characters are digits from 0 through 9, so it follows the format.

Sample Input 2

1 1
---

Sample Output 2

No

S contains unnecessary -s other than the (A+1)-th character, so it does not follow the format.

Sample Input 3

1 2
7444

Sample Output 3

No

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Text.RegularExpressions;

namespace B
{
	internal class Program
	{
		public static void Main(string[] args)
		{
			var line = Console.ReadLine().Split().Select(int.Parse).ToArray();
			var s = Console.ReadLine();

			var regex = new Regex(@"^(\d+)-(\d+)$");
			var match = regex.Match(s);
			if (!match.Success)
			{
				Console.WriteLine("No");
				return;
			}

			for (var i = 0; i < 2; i++)
			{
				if (match.Groups[i + 1].ToString().Length != line[i])
				{
					Console.WriteLine("No");
					return;
				}
			}

			Console.WriteLine("Yes");
		}
	}
}