using System;
public class Hello{
    public static void Main(){
        string[] list = Console.ReadLine().Trim().Split(' ');
        int red = int.Parse(list[0]);
        int blue = int.Parse(list[1]);
        int white = int.Parse(list[2]);
        if((red - blue)>white){
            Console.WriteLine(blue + white);
        }else if((blue - red)>white){
            Console.WriteLine(red + white);
        }else if(red>blue){
            white -=red-blue;
            Console.WriteLine(red + white/2);
        }else if(blue>red){
            white -=blue-red;
            Console.WriteLine(blue + white/2);
        }else{
            Console.WriteLine(red + white/2);
        }
    }
}