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

fn main() {
    let x: i32 = read();
    let y: i32 = read();
    let l: i32 = read();

    let add_step = |a: i32| {
        if a != 0 {
            ((a as f32 / l as f32).ceil() as i32).abs()
        } else {
            0
        }
    };

    let mut step = 0;
    if y < 0 {
        step += 2;
    }
    step += add_step(y);
    if x != 0 {
        step += 1;
    }
    step += add_step(x);
    println!("{}", step);
}