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)

//提出時は下二行と一番下のコメントアウトを外す。
#[macro_use]
mod input {

use std;
use std::io;

const SPLIT_DELIMITER: char = ' ';

/// 空白で区切られた複数の値の読み込む。
/// # Example
/// ```ignore
/// use cp_template::*;
///
/// let (a,b):(usize,usize);
/// input!(a,b);
/// ```
#[macro_export]
#[allow(unused_macros)]
macro_rules! input {
    ( $($x:expr ),*) => {
        {
            let temp_str = input_line_str();
            let mut split_result_iter = temp_str.split_whitespace();
                $(
                let buf_split_result = split_result_iter.next();
                let buf_split_result = buf_split_result.unwrap();
                    ($x) = buf_split_result.parse().unwrap();
                )*
        }
    };
}

/// 文字列を一行読み込む
/// # Example
/// ```ignore
/// use cp_template::*;
///
/// let s = input_line_str();
/// ```
#[allow(dead_code)]
pub fn input_line_str() -> String {
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

/// 一つの変数を出力する。
/// ```
/// use cp_template::*;
///
/// let a=100;
/// p(a);
/// //上と下は等価です。
/// println!("{}",a);
/// ```
#[allow(dead_code)]
pub fn p<T>(t: T)
where
    T: std::fmt::Display,
{
    println!("{}", t);
}

/// 指定した行数を読み込み、二次元配列に変換する。
/// # Examples
/// ```ignore
/// use cp_template::*;
///
/// //10行読み込む。
/// let v = input_vector2d::<usize>(10);
/// ```
#[allow(dead_code)]
pub fn input_vector2d<T>(line: usize) -> Vec<Vec<T>>
where
    T: std::str::FromStr,
{
    let mut v: Vec<Vec<T>> = Vec::new();

    for _ in 0..line {
        let vec_line = input_vector();
        v.push(vec_line);
    }
    v
}

/// 一行読み込み、配列(Vec)に変換する。
/// # Examples
/// ```ignore
/// use cp_template::*;
///
/// let v=input_vector::<usize>();
/// ```
#[allow(dead_code)]
pub fn input_vector<T>() -> Vec<T>
where
    T: std::str::FromStr,
{
    let mut v: Vec<T> = Vec::new();

    let s = input_line_str();
    let split_result = s.split(SPLIT_DELIMITER);
    for z in split_result {
        let buf = match z.parse() {
            Ok(r) => r,
            Err(_) => panic!("Parse Error"),
        };
        v.push(buf);
    }
    v
}

/// String(str)を配列(Vec<char>)に変換する。
/// # Examples
/// ```ignore
/// use cp_template::*;
///
/// let s = String::from("abc");
/// let v = str2vec(&s);
/// let v = str2vec(&input_line_str());
/// ```
#[allow(dead_code)]
pub fn str2vec(s: &str) -> Vec<char> {
    let mut v: Vec<char> = Vec::new();
    for c in s.chars() {
        v.push(c);
    }
    v
}

}

//提出用
#[allow(unused_imports)]
use input::*;

fn main() {
    let (a, b): (usize, usize);
    input!(a, b);
    let s = str2vec(&input_line_str());
    let mut flag = true;
    if s.len() != a + b + 1 {
        flag = false;
    }
    for z in 0..s.len() {
        if z == a {
            if s[z] != '-' {
                flag = false;
            }
        } else {
            if s[z] == '-' {
                flag = false;
            }
        }
    }
    if flag {
        println!("Yes");
    } else {
        println!("No");
    }
}