using System;

namespace AtCorder
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var abcArr = Console.ReadLine().Split(' ');
            var a = int.Parse(abcArr[0]);
            var b = int.Parse(abcArr[1]);
            var c = int.Parse(abcArr[2]);

            var result = Math.Min(a, b);

            var difAB = Math.Max(a, b) - result;

            if (difAB < c)
            {
                result += difAB + ((c - difAB) / 2);
            }
            else
            {
                result += c;
            }

            Console.Write(result);
        }
    }
}