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: Wrong Answer)

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

namespace AtCoder
{
    internal static class Program
    {
        private static void Main()
        {
            int[] ab = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
            string text = Console.ReadLine();
            string res = "Yes";
            
            for (int i = 0; i < ab[0]; i++)
                if (!char.IsDigit(text[i]))
                    res = "No";

            if (text[ab[0]] != '-')
                res = "No";

            for (int i = ab[0] + 1; i < ab[1]; i++)
                if (!char.IsDigit(text[i]))
                    res = "No";
            

            Console.WriteLine(res);
        }
    }
}