using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new long[t];
        for (var u = 0; u < t; ++u)
        {
            var c = NList;
            var (l, r) = (c[0], c[1]);
            ans[u] = Xor(l, r);
        }
        WriteLine(string.Join("\n", ans));
    }
    static long Xor(long l, long r)
    {
        if (l == r) return l * 2;
        else
        {
            var min1 = l * 2 + 1;
            var max1 = l + r;
            while (min1 % 4 != max1 % 4) --max1;
            return (max1 - min1 + 4) / 4 % 2 + ((r - l) % 4 == 0 ? (l + r - ((l + r) % 2)) : 0);
        }
    }
}