#include<bits/stdc++.h>

using namespace std;
#define int long long
#define endl '\n'
#define PII pair<int,int>
mt19937_64 rnd(time(0));

void solve() {
    int n;
    cin >> n;
    vector<PII > a(n + 1);
    for (int i = 1; i <= n; i++)
        cin >> a[i].first >> a[i].second;
    int ans = 0;
    for (int j = 30; j >= 0; j--) {
        int l = ans | (1 << j), r = ans | ((1 << j + 1) - 1);
        bool ok = 1;
        for (int i = 1; i <= n; i++) {
            if (max(l, a[i].first) > min(r, a[i].second)) {
                ok = 0;
            }
        }
        if (ok) {
            for (int i = 1; i <= n; i++) {
                a[i].first = max(l, a[i].first);
                a[i].second = min(a[i].second, r);
            }
        } else {
            for (int i = 1; i <= n; i++) {
                a[i].first %= (1 << j);
                a[i].first |= ans;
            }
        }
        ans |= ok << j;
    }
    cout << ans << endl;
}

/*
 27 30
5 8
14 15
10 11
0 14
8 15
12 13
0 11
10 12
8 12
8
 */
signed main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t = 1;
    cin >> t;
    while (t--)
        solve();
    return 0;
}