import java.util.*;

class Main{
    public static void main (String[] args) {
        
        Scanner s = new Scanner(System.in);
        int X =s.nextInt();
        int Y =s.nextInt();
        int Z =s.nextInt();
            int p = Math.max(X,Y);
            int q = Math.min(X,Y);
            int r = p-q;

                int m,n;
                if (r <= Z) {
                     m = r;
                     n = (Z-r)/2;
                }else{
                     m = Z;
                     n = 0;
                }
                System.out.println(q+m+n);
    }
}