#include<bits/stdc++.h>
#include<vector>
using namespace std;

typedef long long ll;
const int N = 100005;

int a[N];
int ct[N];

void solve() {
	int n;
	cin >> n;	
	vector<int> c(n);
	for (int i = 1; i <= n; i++) {
		ct[i] = 0;
	}

	for (int i = 1; i <= n; i++) {
		int x;
		cin >> x;
		ct[x]++;
		c[x - 1]++;
	}
	if (n == 1) {
		cout << c[0] << '\n';
		return;
	}
//	sort(c.begin(), c.end());

	int cntx = 0, cnty = 0;

	for (int i = 1; i <= n; i++) {
		if (ct[i] >= cntx) {
			cnty = cntx;
			cntx = ct[i];
		} else if (ct[i] > cnty) {
			cnty = ct[i];
		}
	}

	int ans = cntx | cnty;

	int k = cntx | cnty;
	while(k > (k & (-k))) k -= k & (-k);
	k--;
	if (k < 0) k = 0;
	ans |= k;
	cout << ans  << '\n';

}

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

	int T;
	cin >> T;
	while(T--) {
		solve();
	}


	return 0;
}