#include <bits/stdc++.h>
using namespace std;
const int MAXN = 300005;
int main() {
	int t; scanf("%d", &t); while (t--) {
		int n; scanf("%d", &n); map<int, int> mp;
		for (int i = 1; i <= n; i++) {int a; scanf("%d", &a); mp[a]++;}
		vector<int> p; for (auto x : mp) p.push_back(x.second);
		reverse(p.begin(), p.end()); int ans = n;
		for (int x : p) {
			if (n > x) ans--, n -= x + 1;
			else n = -1;
		}
		printf("%d\n", ans);
	}
}