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;

class Program
{
	static void Main()
	{
		var AB = Array.ConvertAll(Console.ReadLine().Split(new[] { ' ' }), number => int.Parse(number));
		var S = Console.ReadLine();

		var isWrite = true;
		if (S.Length == AB[0] + AB[1] + 1) {
			for (var i = 0; i < S.Length; ++i) {
				if (i == AB[0]) {
					if (S[i] != '-') {
						isWrite = false;
					}
				} else {
					if (S[i] < '0' || S[i] > '9') {
						isWrite = false;
					}
				}
			}
		} else {
			isWrite = false;
		}

		Console.WriteLine(isWrite ? "Yes" : "No");

		//デバッグ実行での確認用。そのまま提出しても問題なし
		Console.ReadKey();
	}
}