fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let mut x: f64 = itr.next().unwrap().parse().unwrap();
    let mut y: f64 = itr.next().unwrap().parse().unwrap();
    let r: f64 = itr.next().unwrap().parse().unwrap();
    x = x.abs();
    y = y.abs();

    let ans = (x + y + r * (2 as f64).sqrt()) as i32 + 1;
    println!("{}", ans);
}