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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		String s = sc.next();
		StringBuilder sb = new StringBuilder();
		for(int i = 0 ; i < a ; i++) sb.append(".");
		sb.append("-");
		for(int i = 0 ; i < b ; i++) sb.append(".");
		if(s.substring(0, a).matches(sb.toString().substring(0, a)) && s.substring(a, a + 1).equals(sb.toString().substring(a, a + 1)) && s.substring(a + 1).matches(sb.toString().substring(a + 1)) && !s.substring(0, a).contains("-") && !s.substring(a + 1).contains("-")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
}