#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define lowbit(x) (x & -x)
const int N = 2e5 + 5;
const int mod = 1e9 + 7;
int n, a[N], c[N], cnt[N];
void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
        c[i] = cnt[i] = 0;
    for (int i = 1; i <= n; i++)
        cin >> a[i], c[a[i]]++;
    for (int i = 1; i <= n; i++)
        if (c[i])
            cnt[c[i]]++;
    int ans = 0;
    vector<int> tmp;
    for (int i = 1; i <= n; i++)
        if (cnt[i])
        {
            ans = max(ans, i);
            tmp.push_back(i);
            if (cnt[i] >= 2)
                ans = max(ans, i + (lowbit(i) - 1));
        }
    for (auto x : tmp)
        for (auto y : tmp)
            if (x != y)
            {
                ans = max(ans, x | y);
                int tmp = x & y;
                if (tmp)
                    ans = max(ans, x | y | ((1 << __lg(tmp)) - 1));
            }
    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;
}