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

            if(s[a] == '-'){
                var x = s.Substring(0, a);
                var y = s.Substring(a + 1, b);

                var o = 0;
                if(int.TryParse(x, out o) && int.TryParse(y, out o)){
                    Console.WriteLine("Yes");
                }else{
                    Console.WriteLine("No");
                }
            }else{
                Console.WriteLine("No");
            }
        }
    }
}