#include <iostream>
using namespace std;
 
long long t, n, temp, x, s;
long long arr[1001];
 
int main() {
	cin >> t;
	for (int i = 0; i < t; i++) {
		cin >> n;
		for (int j = 1; j <= n; j++) {
			cin >> arr[j];
		}
		for (int j = 1; j <= n; j++) {
			temp = arr[j];
			x = j-1;
			while (x>0 && arr[x] <= temp) {
				arr[x+1] = arr[x];
				x--;
			}
			arr[x+1] = temp;
		}
		s = 1;
		while (arr[s] >= s) {
			s++;
		}
		cout << s-1 << endl;
	}
	return 0;
}

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

NAo1CjQgMyAxIDQgNQo0CjQgNCA0IDQKMwoxIDEgMQo1CjUgNSAxIDEgNQ==

4
5
4 3 1 4 5
4
4 4 4 4
3
1 1 1
5
5 5 1 1 5