use std::io::{self, BufReader, BufWriter, Read, Write};

fn main() {
    let stdin = io::stdin();
    let mut stdin = BufReader::new(stdin.lock());
    let stdout = io::stdout();
    let mut stdout = BufWriter::new(stdout.lock());

    let mut buf = String::new();
    stdin.read_to_string(&mut buf).unwrap();

    let mut iter = buf.split_whitespace();
    let x: i64 = iter.next().unwrap().parse().unwrap();
    let y: i64 = iter.next().unwrap().parse().unwrap();
    let l: i64 = iter.next().unwrap().parse().unwrap();
    let mut n = 0;

    if y >= 0 {
        if y.abs() <= l && y != 0 {
            n += 1;
        } else {
            n += y.abs() / l;

            if y.abs() % l != 0 {
                n += 1;
            }
        }

        if x != 0 {
            n += 1;
        }

        if x.abs() <= l && x != 0 {
            n += 1;
        } else {
            n += x.abs() / l;

            if x.abs() % l != 0 {
                n += 1;
            }
        }
    } else {
        n += 2;

        if x.abs() <= l && x != 0 {
            n += 1;
        } else {
            n += x.abs() / l;

            if x.abs() % l != 0 {
                n += 1;
            }
        }

        if y.abs() <= l && y != 0 {
            n += 1;
        } else {
            n += y.abs() / l;

            if y.abs() % l != 0 {
                n += 1;
            }
        }
    }

    writeln!(&mut stdout, "{}", n).unwrap();
}