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 test
{
    class Program {
        public static void Main(string[] args)
        {
            var postalFormat = 
                Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var target = Console.ReadLine();
            if (Regex.IsMatch(
                target,
                PostalFormat.ToPostalFormat(postalFormat[0], postalFormat[1])))
            {
                Console.WriteLine("Yes");
            }
            else Console.WriteLine("No");
        }
    }

    static class PostalFormat {
        public static string ToPostalFormat(
            int former,
            int later)
        {
            return String.Concat(Enumerable.Repeat(@"\d", former).ToArray()) +
                         "-" +
                         String.Concat(Enumerable.Repeat(@"\d", later).ToArray());
        }
    }
}