fn calc(x: i32, y: i32, mv: i32) -> i32 {
    let _f = { |n: i32| if n == 0 { 0 } else { n / n.abs() } };
    let move_turn = match (_f(x), _f(y)) {
        (_, -1) => 2,
        (0, _) => 0,
        (_, _) => 1,
    };

    let (_x, _y, mv) = (x.abs() as f64, y.abs() as f64, mv as f64);
    ((_x / mv).ceil() + (_y / mv).ceil() + (move_turn as f64)) as i32
}

fn _read() -> (i32, i32, i32) {
    fn _read_to<T: std::str::FromStr>() -> T {
        let mut _s = String::new();
        std::io::stdin().read_line(&mut _s).ok();
        _s.trim().parse().ok().unwrap()
    }

    (_read_to(), _read_to(), _read_to())
}

fn main() {
    let (x, y, mv) = _read();
    println!("{}", calc(x, y, mv));
}