#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define dbg(a,b,c,d) cerr<<a<<"  "<<b<<"  "<<c<<"  "<<d<<endl;
#define kill(a) {cout<<a<<endl;continue;}
#define KILL(a) {cout<<a<<endl;return 0;}
#define debug cerr<<"Error Found"<<endl;
#define mem(a,b) memset(a,b,sizeof(a))
#define lcm(a, b) (a/__gcd(a,b))*b
#define w(t) cin>>t;while(t--)
#define pi  2 * acos(0.0)
#define endl "\n"
int t, cs = 1;
const int mxn = 1e3 + 3, mod = 1e9 + 7;

int32_t main()
{
    //fast;
   w(t)
   {
       int n;
       cin >> n;
       int64_t sum = 0;
       for(int i = 0, a; i < n; i++)cin >> a, sum += a;
       int64_t mex = 0;
       while(1LL * mex * (mex + 1) / 2 <= sum)mex++;
       cout << mex << endl;
   }


}