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;

namespace AtCoderTest
{
    class Program
    {
        static int sec1_length;
        static int sec2_length;

        static void Main(string[] args)
        {
            string line;

            for (int i = 0; (line = Console.ReadLine()) != null; i++)
            {
                if (i == 0)
                {
                    string[] words = line.Split(' ');
                    sec1_length = int.Parse(words[0]);
                    sec2_length = int.Parse(words[1]);
                }
                else if (i == 1)
                {
                    Console.WriteLine(formatCheck(line));
                }
            }
        }

        static string formatCheck(string str)
        {
            string[] words = str.Split('-');
            int len = words.Length;
            int num1;
            int num2;
            
            if (len != 2)
            {
                return "No";
            }

            if (words[0].Length != sec1_length || words[1].Length != sec2_length)
            {
                return "No";
            }

            try
            {
                num1 = int.Parse(words[0]);
                num2 = int.Parse(words[1]);
            }
            catch
            {
                return "No";
            }

            if (num1 > 0 && num2 > 0)
            {
                return "Yes";
            }
            else
            {
                return "No";
            }
        }
    }
}