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

    if ab[0] < ab[1] {
        println!("{}", (ab[0] - 1) + (ab[1] - ab[0] - 1));
    } else {
        println!("{}", (ab[0] - ab[1] - 1) + (2_000_000_000 - ab[0]));
    }
}