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;
using System.Threading.Tasks;

namespace ABC084B
{
    class Program
    {
        static void Main(string[] args)
        {
            var AB = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var s = Console.ReadLine();

            string sa = s.Substring(0, AB[0]);
            string sb = s.Substring(AB[0] + 1);
            bool ans = true;
            if (s.Count() != AB.Sum() + 1)
            {
                ans = false;
            }
            if (s[AB[0]] != '-')
            {
                ans = false;
            }
            foreach (char c in sa)
            {
                if (!char.IsNumber(c)) ans = false;
            }
            foreach (char c in sb)
            {
                if (!char.IsNumber(c)) ans = false;
            }

            if (ans == true) Console.WriteLine("Yes");
            else Console.WriteLine("No");
            Console.ReadKey();
        }
    }
}