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 AtCoder.Abc
{
    class QuestionB
    {
        public static void Main(string[] args)
        {
            var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);

            // 整数配列の入力
            var inputLongArray = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();

            // 文字列の入力
            string s = Console.ReadLine();

            string result = "Yes";

            var ss = 0;

            if (s.Length != inputLongArray[0] + inputLongArray[1] + 1) {
                result = "No";
            }else if(s[inputLongArray[0]] != '-') {
                result = "No";
            } else if(int.TryParse(s.Substring(0, inputLongArray[0]), out ss) == false) {
                result = "No";
            }else if (int.TryParse(s.Substring(inputLongArray[0] + 1), out ss) == false) {
                result = "No";
            }

            Console.WriteLine(result);

            Console.Out.Flush();
        }
    }
}