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.Linq;
using System.Text;

class Program
{
    static void Main(string[] args)
    {
        var line = Console.ReadLine();
        var formerNum = int.Parse(line.Split(' ')[0]);
        var latterNum = int.Parse(line.Split(' ')[1]);
        var str = Console.ReadLine();

        if (str[formerNum] != '-' || str.Length != formerNum + latterNum + 1)
        {
            Console.WriteLine("No");
            return;
        }

        var formerStr = str.Substring(0, formerNum);
        var latterStr = str.Substring(formerNum + 1, latterNum);
        
        foreach (char c in formerStr + latterStr)
        {
            if (c < '0' || '9' < c)
            {
                Console.WriteLine("No");
                return;
            }
        }

        Console.WriteLine("Yes");
    }
}