use std::io::*;
use std::str::FromStr;

#[allow(dead_code)]
fn get_line() -> String {
    let stdin = stdin();
    let mut line = String::new();
    stdin.lock().read_line(&mut line).expect("io error.");
    line.trim().to_string()
}

#[allow(dead_code)]
fn get_word<T: FromStr>() -> T {
    (&get_line()).parse().ok().expect("parse error.")
}

#[allow(dead_code)]
fn get_vec<T: FromStr>() -> Vec<T> {
    (&get_line()).split(' ').map(|x| x.parse().ok().expect("parse error.")).collect()
}

fn main() {
    let x = get_word::<i64>().abs();
    let y = get_word::<i64>().abs();
    let l = get_word::<i64>();

    let mut ans = (x + l - 1) / l + (y + l - 1) / l;

    if x > 0 && y > 0 {
        ans += 1;
    }

    println!("{}", ans);
}