#include<bits/stdc++.h>
using namespace std;
using ll=long long;

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t;
    cin >> t;
    while(t--){
        ll L, R;
        cin >> L >> R;
        //k = 1 から k = (L + R) / 2までの総和
        ll MID = (L + R - 1) / 2 - L + 1;
        ll sumv = MID * (MID + 1) /2;
        MID &= 1;
        sumv &= 1;
        if(L == R){
            cout << L + R << endl;
            continue;
        }
        if((L + R)&1){
            cout << sumv << endl;
        }else{
            cout << (MID^1 ?(sumv^(L + R)): sumv )<< endl;
        }
    }
}