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

namespace AtCoder
{
	class Program
	{
		static void Main(string[] args)
		{
			Question.Exec();
		}
	}

	public static class Question
	{
		public static bool IsOdd(long n)
		{
			bool isOdd = n % 2 == 1;
			return isOdd;
		}

		public static void Exec()
		{
			var array = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();
			int a = array[0];
			int b = array[1];
			string s = Console.ReadLine();

			if (s.Length != a + b + 1) {
				Console.WriteLine($"No");
				Console.ReadKey();
				return;
			}

			if (s[a] != '-') {
				Console.WriteLine($"No");
				Console.ReadKey();
				return;
			}

			string astr = s.Substring(0, a);
			string bstr = s.Substring(a + 1, b);
			try {
				int.Parse(astr);
				int.Parse(bstr);
			} catch {
				Console.WriteLine($"No");
				Console.ReadKey();
				return;
			}

			Console.WriteLine($"Yes");

			Console.ReadKey();
		}
	}
}