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;

class Program
{
    static void Main(string[] args)
    {
        var ab = Console.ReadLine().Split(' ');
        var a = int.Parse(ab[0]);
        var b = int.Parse(ab[1]);

        var s = Console.ReadLine();
        for (int i = 0; i <= a + b; i++)
        {
            if (i == a)
            {
                if (s[i] != '-')
                {
                    Console.WriteLine("No");
                    return;
                }
            }
            else
            {
                if ('0' > s[i] || s[i] > '9')
                {
                    Console.WriteLine("No");
                    return;
                }
            }
        }

        Console.WriteLine("Yes");
    }
}