import java.util.*;

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