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 Rust (1.42.0) (judge verdict: Accepted)

use proconio::input;
use proconio::marker::Chars;

fn main() {
    input! {
        a: usize,
        b: usize,
        s: Chars
    };
    let mut is_ok = true;
    for (i, &s_i) in s.iter().enumerate() {
        if i < a {
            if !s_i.is_digit(10) {
                is_ok = false;
                break;
            }
        } else if i == a {
            if s_i != '-' {
                is_ok = false;
                break;
            }
        } else {
            if !s_i.is_digit(10) {
                is_ok = false;
                break;
            }
        }
    }
    println!("{}", if is_ok { "Yes" } else { "No" });
}