#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++)
                if (a[i].first & (1 << j))
                    a[i].first ^= (1 << j);
        }
        else
        {
            for (int i = 1; i <= n; i++)
                if (!(a[i].first & (1 << j)))
                    a[i].first ^= (1 << j);
        }
        ans |= ok << j;
    }
    cout << ans << endl;
}
signed main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t = 1;
    cin >> t;
    while (t--)
        solve();
    return 0;
}