#include <bits/stdc++.h> 
using namespace std;
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

typedef long long ll;
typedef vector<ll> vi;
typedef long double ld;
#define ff          first
#define ss          second
#define all(a)      a.begin(),a.end()
#define rall(a)     a.rbegin(),a.rend()
#define pb          push_back
#define mp          make_pair
#define bits(x) __builtin_popcountll(x)
#define endl "\n"
#define M 998244353
#define mod 1000000007

ll binToDec(string s) { return bitset<64>(s).to_ullong(); }
string decToBin(ll a) { return bitset<64>(a).to_string(); }

void solve() {
  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";
}

int main(){

    auto begin = std::chrono::high_resolution_clock::now();
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll test=1;
    cin>>test;

    for(int i=1;i<=test;i++) {
        //cout << "Case #" << i << ": ";
        
        solve();
    }
    
	  auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";

}