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.
8
2
2 3
3
3 4 5
1
1
1
2
1
3
1
4
1
12071207
5
5 5 5 9 14

1
2
0
-1
1
1
1
4

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.StringTokenizer;

public class C {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(
                    new InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() { return Integer.parseInt(next()); }

        long nextLong() { return Long.parseLong(next()); }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try {
                str = br.readLine();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
    public static void main(String[] args){
        FastReader sc = new FastReader();
        int t = sc.nextInt();
        StringBuilder s = new StringBuilder();
        while (t-->0){
            int n = sc.nextInt();
            int[] a = new int[n];
            boolean[] p = new boolean[n+1];
            for (int i=1;i<=n;i++){
                p[i] = false;
            }
            PriorityQueue<Integer> maxHeap = new PriorityQueue<>(new Comparator<Integer>() {
                @Override
                public int compare(Integer o1, Integer o2) {
                    return o2-o1;
                }
            });
            for (int i=0;i<n;i++){
                a[i] = sc.nextInt();
                if (a[i]<=n){
                    if (p[a[i]]){
                        maxHeap.add(a[i]%((a[i]/2)+1));
                    }else {
                        p[a[i]] = true;
                    }
                }else {
                    maxHeap.add(a[i]%((a[i]/2)+1));
                }
            }

            int count = 0;
            for (int i=n;i>0;i--){
                if (!p[i]){
                    if (maxHeap.peek()<i){
                        count = -1;
                        break;
                    }else {
                        maxHeap.poll();
                        count++;
                    }
                }
            }
            s.append(count+"\n");

        }
        System.out.println(s);
    }
}
