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.Collections.Generic;
using static System.Console;

class Program {
	static void Main() {
		var A = NextInt();
		var B = NextInt();
		var S = ReadLine();

		WriteLine(Judge(A, B, S) ? "Yes" : "No");
	}

	static bool Judge(int A, int B, string S) {
		var i = 0;
		foreach (var c in S) {
			if (i < A || i + B >= S.Length) {
				if (c == '-') {
					return false;
				}
			} else if (c != '-') {
				return false;
			}
			i++;
		}
		return true;
	}

	static int NextInt() {
		return int.Parse(NextString());
	}

	static string NextString() {
		var result = new List<char>();
		while (true) {
			int next = Read();
			if (next < 0)
				break;
			var nextChar = (char)next;
			if (!char.IsWhiteSpace(nextChar))
				result.Add(nextChar);
			else if (nextChar != '\r')
				break;
		}
		return string.Join("", result);
	}
}