use std::str::FromStr;
use std::fmt::Debug;
use std::cmp;
#[allow(dead_code)]
fn read_as_vec<T>() -> Vec<T>
where T: FromStr, <T as FromStr>::Err : Debug{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().split_whitespace().map(|c| T::from_str(c).unwrap()).collect()

}

#[allow(dead_code)]
fn read_as_string() -> String{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

fn main(){
    let line = read_as_vec::<usize>();
    let (a, b) = (line[0], line[1]);
    let mut s = read_as_string().chars().collect::<Vec<char>>();
    if s[a] != '-'{
        s.remove(a);
    }

    if s.into_iter().all(|c| c.is_numeric()){
        println!("Yes");
    }else{
        println!("No");
    }
}
