fn main() {
    let mut input = String::new();
    let _ = std::io::stdin().read_line(&mut input);
    let input: Vec<i32> = input.trim().split_whitespace().map(|n| n.parse().unwrap()).collect();

    let x = input[0];
    let y = input[1];
    let r = input[2];

    let s = r as f64 / 2_f64.sqrt();
    let x2 = x.abs() as f64 + s;
    let y2 = y.abs() as f64 + s;
    let result = (x2 + y2).ceil() as i32;

    println!("{}", result);
}