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#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

long long comb(long long n, int k) {
    if (n < k) return 0;
    if (k == 3) return n * (n - 1) * (n - 2) / 6;
    if (k == 2) return n * (n - 1) / 2;
    return 1;
}

long long find_s_min(long long sum_a) {
    long long s = 1;
    while (comb(s, 3) < sum_a) {
        s++;
    }
    return s;
}

void generate_partitions(int n, long long S, vector<long long>& current, vector<vector<long long>>& partitions) {
    if (n == 1) {
        current.push_back(S);
        partitions.push_back(current);
        current.pop_back();
        return;
    }
    for (long long first = 0; first <= S; first++) {
        current.push_back(first);
        generate_partitions(n - 1, S - first, current, partitions);
        current.pop_back();
    }
}

// Function to solve a single test case
long long solve_case(int n, const vector<long long>& a) {
    long long sum_a = 0;
    for (long long ai : a) {
        sum_a += ai;
    }
    if (sum_a == 0) {
        return 0;
    }
    long long s_min = find_s_min(sum_a);
    for (long long S = s_min; ; S++) {
        vector<vector<long long>> partitions;
        vector<long long> current;
        generate_partitions(n, S, current, partitions);
        for (const vector<long long>& k : partitions) {
            bool valid = true;
            for (int i = 0; i < n; i++) {
                long long ai = a[i];
                long long ki = k[i];
                long long L = 0, R = 0;
                for (int j = 0; j < i; j++) {
                    L += k[j];
                }
                for (int j = i + 1; j < n; j++) {
                    R += k[j];
                }
                long long total = comb(ki, 3) + comb(ki, 2) * (S - ki) + L * ki * R;
                if (total < ai) {
                    valid = false;
                    break;
                }
            }
            if (valid) {
                return S;
            }
        }
    }
    return -1;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;
        vector<long long> a(n);
        for (int i = 0; i < n; i++) {
            cin >> a[i];
        }
        cout << solve_case(n, a) << '\n';
    }
    return 0;
}