fn main() {
    let x: i32 = read::<i32>().abs();
    let y: i32 = read::<i32>().abs();
    let l: i32 = read();

    let div_ceil = |a: &i32, b: &i32| -> i32 {
        if a % b == 0 {
            a / b
        }
        else {
            a / b + 1
        }
    };

    //原点の場合
    if x == 0 && y == 0 {
        println!("0");
    }
    //軸上の場合
    else if x == 0 {
        println!("{}", div_ceil(&y, &l));
    }
    else if y == 0 {
        println!("{}", div_ceil(&x, &l) + 1);
    }

    else if y > 0  {
        println!("{}", div_ceil(&x, &l) + div_ceil(&y, &l) + 1)
    }
    else {
        println!("{}", div_ceil(&x, &l) + div_ceil(&y, &l) + 2)

    }
}

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 read_vec<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().split_whitespace()
        .map(|e| e.parse().ok().unwrap()).collect()
}