import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int x = Math.abs(sc.nextInt());
        int y = Math.abs(sc.nextInt());
        int r = sc.nextInt();
        int times = (int)Math.ceil(r / (Math.sqrt(2) / 2));
        System.out.println(x + y + times);
    }
}