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 (1.15.1) (judge verdict: Accepted)

#[allow(unused_imports)]
use std::io::*;
#[allow(unused_imports)]
use std::str::*;
#[allow(unused_imports)]
use std::collections::*;

#[allow(dead_code)]
fn read<T: FromStr>(s: &mut StdinLock) -> T {
    let s = s.by_ref().bytes().map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>();
    s.parse::<T>().ok().unwrap()
}

#[allow(unused_macros)]
macro_rules! p {
    ($x:expr) 
    => (println!("{}", $x));
    ($x:expr, $y:expr)
    => (println!("{} {}", $x, $y));
    ($x:expr, $y:expr, $z:expr) 
    => (println!("{} {} {}", $x, $y, $z));
}

#[allow(unused_macros)]
macro_rules! pl {
    ($x:expr) 
    => (println!("{}", $x));
    ($x:expr, $y:expr)
    => (println!("{}\n{}", $x, $y));
    ($x:expr, $y:expr, $z:expr) 
    => (println!("{}\n{}\n{}", $x, $y, $z));
}

fn main() {
    let s = stdin();
    let mut s = s.lock();
    let s = &mut s;

    let a: usize = read(s);
    let b: usize = read(s);
    let s: String = read(s);
    let s: Vec<char> = s.chars().collect();
    let mut ok = true;
    for i in 0..(a+b+1) {
        if (i != a) {
            ok &= s[i].is_digit(10);
        } else {
            ok &= s[i] == '-';
        }
    }
    p!(if ok { "Yes" } else { "No"});
}