#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long N = 1e6 + 5;
long long solve() {
  long long n;
  cin >> n;
  map<long long, long long> mp;
  vector<long long> v(n);
  for (long long &x : v) {
    cin >> x;
    mp[x]++;
  }
  long long ans = 0;
  for (auto it : mp) {
    long long usable = (long long)mp.size() - 1;
    long long use = min(usable, it.second);
    if (it.second > usable + 1) {
      ++use;
    }
    ans = max(ans, use);
  }
  cout << ans << '\n';
  return 0;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  long long T = 1;
  cin >> T;
  for (long long i = 1; i <= T; ++i) solve();
  return 0;
}
