#include <bits/stdc++.h> // {{{

#include <version>
#ifdef __cpp_lib_ranges_enumerate
#include <ranges>
namespace rv = std::views;
namespace rs = std::ranges;
#endif

// https://codeforces.com/blog/entry/96344

#pragma GCC optimize("O2,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

using namespace std;

using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
using f64 = double;
using f128 = long double;

#if __cplusplus >= 202002L
template <typename T> constexpr T MIN = std::numeric_limits<T>::min();

template <typename T> constexpr T MAX = std::numeric_limits<T>::max();

template <typename T> [[nodiscard]] static T sc(auto &&x) {
  return static_cast<T>(x);
}

template <typename T> [[nodiscard]] static T sz(auto &&x) {
  return static_cast<T>(x.size());
}
#endif

static void NO() { std::cout << "NO\n"; }

static void YES() { std::cout << "YES\n"; }

template <typename T> using vec = std::vector<T>;

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define ff first
#define ss second

#ifdef LOCAL
#define db(...) std::print(__VA_ARGS__)
#define dbln(...) std::println(__VA_ARGS__)
#else
#define db(...)
#define dbln(...)
#endif
//  }}}

void solve() {
  u32 n;
  cin >> n;

  vec<u32> a(n);
  map<u32, u32> f;
  for (auto &e : a) {
    cin >> e;
    ++f[e];
  }

  i32 l = 0, r = n / 2;

  while (l <= r) {
    i32 m = l + (r - l) / 2;

    bool ok = false;
    for (auto &[number, frequency] : f) {
      if (frequency >= m) {
        i32 rest = (i32)f.size() - (frequency == m);

        if (rest >= m) {
          ok = true;
          break;
        }
      }
    }

    if (ok) {
      l = m + 1;
    } else {
      r = m - 1;
    }
  }

  println("{}", r);
}

int main() { // {{{
  std::cin.exceptions(std::cin.failbit);

#ifdef LOCAL
  std::cerr.rdbuf(std::cout.rdbuf());
  std::cout.setf(std::ios::unitbuf);
  std::cerr.setf(std::ios::unitbuf);
#else
  std::cin.tie(nullptr)->sync_with_stdio(false);
#endif

  u32 tc = 1;
  std::cin >> tc;

  for (u32 t = 0; t < tc; ++t) {
    solve();
  }

  return 0;
}
// }}}