#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < n; i++)
#define rrep(i,n) for (int i = n-1; i >= 0; i--)
#define rep2(i,a,b) for (int i = a; i < b; i++)
#define rrep2(i,a,b) for (int i = a-1; i >= b; i--)
#define rep3(i,a,b,c) for (int i = a; i < b; i+=c)
#define rrep3(i,a,b,c) for (int i = a-1; i >= b; i-=c)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

int t;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>t;
    while(t--){
        ll l,r;cin>>l>>r;
        ll a=r-l+1;
        if(a%4==0){
            if((a/4)%2==0)cout<<0<<"\n";
            else cout<<((2*l)^(2*l+1))<<"\n";
        }else if(a%4==1){
            if((a/4)%2==0)cout<<l+r<<"\n";
            else cout<<((2*l)^(2*l+1)^(l+r))<<"\n";
        }else{
            if((a/4)%2==1)cout<<0<<"\n";
            else cout<<((2*l)^(2*l+1))<<"\n";
        }
    }
}