using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace lecture
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] line = Console.ReadLine().Split();
            int a = int.Parse(line[0]);
            int b = int.Parse(line[1]);
            int r = int.Parse(line[2]);
            a = Math.Abs(a);
            b = Math.Abs(b);

            int ans = (int)(a + b + r * Math.Sqrt(2) + 1);

            Console.WriteLine(ans);
        }
    }
}