use std::io::{stdin, Read, StdinLock};
use std::str::FromStr;

struct Input {
    x: f64,
    y: f64,
    l: f64,
}

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

fn solve(input: Input) {
    let n = if input.x == 0.0 && input.y >= 0.0 {
        0
    } else if input.y >= 0.0 {
        1
    } else {
        2
    };

    println!(
        "{}",
        (n as f64) + (input.x / input.l).abs().ceil() + (input.y / input.l).abs().ceil()
    );
}

fn next_token<T: FromStr>(cin_lock: &mut StdinLock) -> T {
    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>()
        .parse::<T>()
        .ok()
        .unwrap()
}

fn main() {
    let cin = stdin();
    let mut cin_lock = cin.lock();
    let input = read_input(&mut cin_lock);
    solve(input);
}