#include <iostream>
using namespace std;

long long compute_xor(long long n) {
int mod = n % 4;
if (mod == 0) return n;
else if (mod == 1) return 1;
else if (mod == 2) return n + 1;
else return 0;
}

int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);

int T;
cin >> T;
while (T--) {
long long l, r;
cin >> l >> r;
long long result = compute_xor(r) ^ compute_xor(l - 1);
cout << result << '\n';
}

return 0;
}