use std::io::{self, Read};

#[derive(Debug)]
struct Input {
    x: i32,
    y: i32,
    l: i32,
}

fn next_token(cin_lock: &mut io::StdinLock) -> String {
    cin_lock
        .by_ref()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>()
}

fn read_input(cin_lock: &mut io::StdinLock) -> Input {
    Input {
        x: next_token(cin_lock).parse().unwrap(),
        y: next_token(cin_lock).parse().unwrap(),
        l: next_token(cin_lock).parse().unwrap(),
    }
}

fn solve(input: Input, _cin_lock: &mut io::StdinLock) {
    let n_turns = if input.y < 0 {
        2
    } else if input.x != 0 {
        1
    } else {
        0
    };

    let move_horizontal = (input.x.abs() + (input.l - 1)) / input.l;
    let move_vertical = (input.y.abs() + (input.l - 1)) / input.l;

    let answer = n_turns + move_horizontal + move_vertical;
    println!("{}", answer);
}

fn main() {
    let cin = io::stdin();
    let mut cin_lock = cin.lock();

    let input = read_input(&mut cin_lock);
    solve(input, &mut cin_lock);
}