fn main() {
    let mut xx = String::new();
    std::io::stdin().read_line(&mut xx).ok();
    let xx: Vec<u64> = xx.split_whitespace().flat_map(str::parse).collect();

    match (xx[0] + 1).saturating_sub(xx[1]) {
        0 => println!("YES\n0"),
        n => println!("NO\n{}", n),
    }
}