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.Linq;
using System;

public class Hello
{
    public static void Main()
    {
        var number = "0123456789";
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = int.Parse(line[0]);
        var b = int.Parse(line[1]);
        var s = Console.ReadLine().Trim();
        if (s.Length != a + b + 1) { Console.WriteLine("NO"); goto end; }
        if (s[a] != '-') { Console.WriteLine("NO"); goto end; }
        for (int i = 0; i < a; i++)
            if (!number.Contains(s[i])) { Console.WriteLine("NO"); goto end; }
        for (int i = a + 1; i < b + 1; i++)
            if (!number.Contains(s[i])) { Console.WriteLine("NO"); goto end; }
        Console.WriteLine("YES");
        end:;
    }
}