#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
    }
    int res[101] = {0};
    for (int i = 0; i < n; i++) {
      res[arr[i]]++;
    }
    int cnt[101] = {0};
    for (int i = 0; i < 101; i++) {
      if (res[i] >= 1) {
        res[i]--;
        cnt[i]++;
      }
    }
    int f, s;
    for (int i = 0; i < 101; i++) {
      if (res[i] == 0) {
        f = i;
        break;
      }
    }
    for (int i = 0; i < 101; i++) {
      if (cnt[i] == 0) {
        s = i;
        break;
      }
    }
    cout << f + s << "\n";
  }
}
