import java.util.*;

class Main{
	public static void main(String[] $) {
		Scanner s=new Scanner(System.in);
		int x=s.nextInt(),y=s.nextInt(),z=s.nextInt();
		int r=Math.min(x,y),q=Math.max(x,y)-r;
		System.out.println(r+(q<=z?(q+z)/2:z));
	}
}