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{
	static boolean check(String s, int A) {
		if(s.charAt(A) != '-') return false;
		String before = s.substring(0, A);
		String after = s.substring(A + 1);
		for(int i = 0; i < before.length(); i++) {
			if(!Character.isDigit(before.charAt(i))) return false;
		}
		for(int i = 0; i < after.length(); i++) {
			if(!Character.isDigit(after.charAt(i))) return false;
		}
		return true;
	}
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int A = sc.nextInt(), B = sc.nextInt();
		String S = sc.next();
		System.out.println(check(S, A) ? "Yes" : "No");
	}
}