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

void solve() {

	int n;
	cin >> n;

	map<int, int> mp;
	for (int i = 0 ; i < n ; i++) {
		int x;
		cin >> x;
		mp[x]++;
	}
	vector<int> cnt;
	for (auto [x, c] : mp) {
		cnt.push_back(c);
	}
	sort(cnt.begin(), cnt.end(), greater<int>());
	//cnt.erase(unique(cnt.begin(), cnt.end()), cnt.end());
//	for (auto x : cnt)
//		cout << x << ' ';
//	cout << '\n';
	if (cnt.size() == 1) {
		cout << cnt[0] << '\n';
	} else {
		ll mx = cnt[0] | cnt[1];
		for (int i = 30 ; i > 0 ; i--) {
			if ((cnt[0] & cnt[1]) >> i & 1) {
				mx = max(mx, mx | (1ll << (i - 1)));
				break;
			}
		}
		cout << mx << '\n';
	}

}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t = 1;
	cin >> t;
	while (t--)
		solve();
	return 0;
}