using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var va = Console.ReadLine().Split().Select(long.Parse).ToArray();
            var x = va[0];
            var y = va[1];
            var r = va[2];
            var l = (Math.Sqrt(x * x + y * y) + r) * Math.Sqrt(2.0);
            var L = (int)l + 1;
            Console.WriteLine(L);
            Console.ReadLine();
        }
    }
}