import java.util.Scanner;

class Main {
    public static void main(String[] args) throws Exception {
        Scanner in = new Scanner(System.in);
        int x = in.nextInt();
        int y = in.nextInt();
        int r = in.nextInt();
        double temp = 2 * r / Math.sqrt(2);
        int ans = Math.abs(x) + Math.abs(y) + (int)temp + 1;
        System.out.println(ans);
    }
}