#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int t;
  cin >> t;
  while (t > 0) {
    t--;
    int n;
    cin >> n;
    set<int> st;
    for (int i = 1; i <= n; i++) {
      st.insert(i);
    }
    vector<int> rem;
    for (int i = 0; i < n; i++) {
      int v;
      cin >> v;
      if (st.find(v) != st.end()) {
        st.erase(v);
      } else {
        rem.push_back(v);
      }
    }
    sort(rem.begin(), rem.end());
    reverse(rem.begin(), rem.end());
    int pt = 0;
    bool err = false;
    for (auto &nx : rem) {
      auto it = st.end();
      it--;
      int ctg = (*it);
      if (ctg > (nx - 1) / 2) {
        err = true;
        break;
      }
      st.erase(it);
    }
    if (err) {
      cout << "-1\n";
    } else {
      cout << rem.size() << '\n';
    }
  }
  return 0;
}

### Prompt

Please provide a Cpp coded solution to the problem described below:

Paprika loves permutations. She has an array a_1, a_2, ..., a_n. She wants to make the array a permutation of integers 1 to n.

In order to achieve this goal, she can perform operations on the array. In each operation she can choose two integers i (1 ≤ i ≤ n) and x (x > 0), then perform a_i := a_i mod x (that is, replace a_i by the remainder of a_i divided by x). In different operations, the chosen i and x can be different.

Determine the minimum number of operations needed to make the array a permutation of integers 1 to n. If it is impossible, output -1.

A permutation is an array consisting of n distinct integers from 1 to n in arbitrary order. For example, [2,3,1,5,4] is a permutation, but [1,2,2] is not a permutation (2 appears twice in the array) and [1,3,4] is also not a permutation (n=3 but there is 4 in the array).

Input

Each test contains multiple test cases. The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases. Description of the test cases follows.

The first line of each test case contains an integer n (1 ≤ n ≤ 10^5).

The second line of each test case contains n integers a_1, a_2, ..., a_n. (1 ≤ a_i ≤ 10^9).

It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5.

Output

For each test case, output the minimum number of operations needed to make the array a permutation of integers 1 to n, or -1 if it is impossible.

Example

Input


4
2
1 7
3
1 5 4
4
12345678 87654321 20211218 23571113
9
1 2 3 4 18 19 5 6 7


Output


1
-1
4
2

Note

For the first test, the only possible sequence of operations which minimizes the number of operations is: 

  * Choose i=2, x=5. Perform a_2 := a_2 mod 5 = 2. 



For the second test, it is impossible to obtain a permutation of integers from 1 to n.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int t;
  cin >> t;
  while (t > 0) {
    t--;
    int n;
    cin >> n;
    set<int> st;
    for (int i = 1; i <= n; i++) {
      st.insert(i);
    }
    vector<int> rem;
    for (int i = 0; i < n; i++) {
      int v;
      cin >> v;
      if (st.find(v) != st.end()) {
        st.erase(v);
      } else {
        rem.push_back(v);
      }
    }
    sort(rem.begin(), rem.end());
    reverse(rem.begin(), rem.end());
    int pt = 0;
    bool err = false;
    for (auto &nx : rem) {
      auto it = st.end();
      it--;
      int ctg = (*it);
      if (ctg > (nx - 1) / 2) {
        err = true;
        break;
      }
      st.erase(it);
    }
    if (err) {
      cout << "-1\n";
    } else {
      cout << rem.size() << '\n';
    }
  }
  return 0;
}

```