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;

namespace ABC084
{
    class B
    {
        static void Main(string[] args)
        {
            string[] input = Console.ReadLine().Split(' ');
            int A = int.Parse(input[0]);
            int B = int.Parse(input[1]);

            string S = Console.ReadLine();

            bool res;
            for (int i = 0; i < A; i++)
            {
                res = Char.IsDigit(S[i]);
                if (!res)
                {
                    Console.WriteLine("No");
                    return;
                }
            }

            if (S[A] != '-')
            {
                Console.WriteLine("No");
                return;
            }

            for (int i = A + 1; i < A + 1 + B; i++)
            {
                res = Char.IsDigit(S[i]);
                if (!res)
                {
                    Console.WriteLine("No");
                    return;
                }
            }
            Console.WriteLine("Yes");
        }
    }
}