import java.util.*;

class Main{
    public static void main (String[] args) {
        /* code */
        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 k = Math.max(r,Z);
                int l = Math.min(r,Z);
                int m = k-l;
                int n = (Z-r)/2;
                
                System.out.println(q+l+n);
    }
}