#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int arr[105];
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
    }
    int visited[105] = {0};
    for (int i = 0; i < n; i++) {
      visited[arr[i]]++;
    }
    int flag1 = -1;
    int flag2 = -1;
    for (int i = 0; i < 105; i++) {
      if (visited[i] == 1 and flag1 == -1) {
        flag1 = i;
      }
      if (visited[i] == 0 and flag1 == -1) {
        flag1 = i;
        flag2 = i;
        break;
      } else if (visited[i] == 0 and flag1 != -1) {
        flag2 = i;
        break;
      }
    }
    cout << flag1 + flag2 << endl;
  }
}
