C4DELIMOSTNA4

/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;
import java.lang.Math.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner in=new Scanner(System.in);
        PrintStream out=new PrintStream(System.out);
        int n=in.nextInt();
        int x1,x2;
        int sum=0;
        int d;
        int delta=10001;
        for(int i=0;i<n;i++){
            x1=in.nextInt();
            x2=in.nextInt();
                if(x1>x2){
                    sum+=x1;
                }
                else{
                    sum+=x2;
                }
            d=Math.abs(x1-x2);
                if((d%4!=0) && (d<delta)){
                    delta=d;
                }
            }
            if(sum%4==0){
                if(delta==10001){
                    sum=0;
                }
            else{
                sum=sum-delta;
                }
            }
            out.println(sum);
            }
        }