#include <iostream>
#include <cmath>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int t;
    cin >> t;
    while(t--) {
        int n;
        cin >> n;
        long long sum = 0;
        for(int i = 0; i < n; i++) {
            int x;
            cin >> x;
            sum += x;
        }
        // Solve k*(k+1)/2 <= sum
        // Using quadratic formula: k = floor((-1 + sqrt(1 + 8*sum)) / 2)
        long long k = static_cast<long long>(floor((-1.0 + sqrt(1 + 8.0 * sum)) / 2));
        cout << k + 1 << "\n";
    }
    return 0;
}