/**
 *  @author:   Binoy Barman
 *  @created:  2024-11-05 20:56:16
**/

#include<bits/stdc++.h>
using namespace std;
#define nl '\n'
#define all(v) v.begin(), v.end()
#define Too_Many_Jobs int tts, tc = 1; cin >> tts; hell: while(tts--)
#define Dark_Lord_Binoy ios_base::sync_with_stdio(false); cin.tie(NULL);

#ifdef LOCAL
#include "debug/whereisit.hpp"
#else
#define dbg(...) 42
#endif
#define int long long

int32_t main() {
Dark_Lord_Binoy
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    Too_Many_Jobs {
        int n;
        cin >> n;
        int sum = 0;
        for (int i = 0; i < n; i++) {
            int x;
            cin >> x;
            sum += x;
        }
        int L = 1, H = 2e9, mid, ans = 0;
        while(L <= H) {
            mid = (L + H) / 2;
            int cur = (mid * (mid + 1)) / 2;
            if(cur <= sum) {
                ans = mid;
                L = mid + 1;
            } else {
                H = mid - 1;
            }
        }
        cout << ans + 1 << nl;
    }
    
    return 0;
}