fn main() {
    let mut input = String::new();
    std::io::stdin().read_line(&mut input).ok();
    let input: Vec<f64> = input
        .split_whitespace()
        .map(|n| n.parse().unwrap())
        .collect();

    if let &[x, y, r] = &input[..] {
        let dist = 2f64.sqrt().mul_add(r, x.abs() + y.abs());

        println!("{}", dist.ceil());
    }
}