#include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       int arr[n];       for (int i = 0; i < n; i++) cin >> arr[i];       int counts[n + 1];       memset(counts, 0, sizeof(counts));       if (n == 1) {         cout << 0 << endl;         continue;       }       for (int i = 0; i < n; i++) counts[arr[i]]++;       int dc = 0, rc = INT_MIN;       for (int i = 0; i <= n; i++) {         if (counts[i] > 0) dc++;         rc = max(rc, counts[i]);       }       if (rc > 1) dc--;       if (rc > dc + 1)         cout << dc + 1 << endl;       else         cout << min(dc, rc) << endl;     }     return 0;   }   