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

int main() {
    int t;
    cin >> t;
    for (int qwerty = 0; qwerty < t; qwerty++) {
        int n;
        cin >> n;
        int a[n];
        for (int i = 0; i < n; i++) cin >> a[i];
        int ans = 0;
        for (int k = 0; k < 1<<n; k++) {
            vector<int> v;
            bool valid = true;
            for (int i = 0; i < n; i++) if (k & 1<<i) v.push_back(a[i]);
            if (v.size() >= 3) for (int i = 2; i < v.size(); i++) {
                if (v[i] == v[i-1] || v[i] == v[i-2]) valid = false;
            }
            else if (v.size() == 2) if (v[0] == v[1]) valid = false;
            if (valid) ans = max(ans, (int)v.size());
        }
        cout << ans << "\n";
    }
    return 0;
}