public class Program
{
    public static void Main()
    {
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //st0ring str = Console.ReadLine() ?? string.Empty;

        int red = int.Parse(str[0]);
        int blue = int.Parse(str[1]);
        int white = int.Parse(str[2]);

        if (red > blue)
        {
            int need = red - blue;
            if (white >= 2)
            {
                if(white>=need)
                {
                    white -= need;
                    blue += need;
                }
                else
                {
                    blue += white;
                }

                if (white >= 2)
                {
                    need = white / 2;
                    blue += need;
                }
            }
            Console.WriteLine(blue);
        }
        else if (red < blue)
        {
            int need = blue - red;
            if (white >= 2)
            {
                if(white >= need)
                {
                    white -= need;
                    red += need;
                }
                else
                {
                    red += white;
                }

                if (white >= 2)
                {
                    need = white / 2;
                    red += need;
                }
            }
            Console.WriteLine(red);
        }
        else
        {
            if (white >= 2)
            {
                red += white / 2;
            }
            Console.WriteLine(red);
        }


    }
}