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

/*
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                      o8888888o
                      88" . "88
                      (| -_- |)
                      0\  =  /0
                    ___/`---'\___
                  .' \\|     |// '.
                 / \\|||  :  |||// \
                / _||||| -:- |||||- \
               |   | \\\  -  /// |   |
               | \_|  ''\---/''  |_/ |
               \  .-\__  '-'  ___/-. /
             ___'. .'  /--.--\  `. .'___
          ."" '<  `.___\_<|>_/___.' >' "".
         | | :  `- \`.;`\ _ /`;.`/ - ` : | |
         \  \ `_.   \_ __\ /__ _/   .-` /  /
     =====`-.____`.___ \_____/___.-`___.-'=====
                       `=---='
 
*/

import java.util.*;
import java.math.*;
import java.io.*;
import java.lang.Math.*;

public class KickStart2020 {
	 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());
		}

		float nextFloat() {
			return Float.parseFloat(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	static long gcd(long a, long b) {
		if (b == 0)
			return a;
		return gcd(b, a % b);

	}
	static long lcm(long a, long b) {
		return a / gcd(a, b) * b;
	}

	public static class Pair implements Comparable<Pair> {
		public int index;
		public String value;

		public Pair(int index,String value) {
			this.index = index;
			this.value = value;
		}

		@Override
		public int compareTo(Pair other) {
			// multiplied to -1 as the author need descending sort order
			if(other.index < this.index) return -1;
			if(other.index > this.index) return 1;
			return 0;
		}
		@Override
		public String toString() {
			return this.index + " " + this.value;
		}
	}
	static boolean isPrime(long d) {
		if (d == 3)
			return false;
		for (int i = 2; i <= (long) Math.sqrt(d); i++) {
			if (d % i == 0)
				return false;
		}
		return true;
	}
	static void decimalTob(int n, int k, Stack<Integer> ss) {
          int x = n % k;
          int y = n / k;
          ss.push(x);
          if(y > 0) {
        	   decimalTob(y, k, ss);
          }
	}
	static long powermod(long x, long y, long mod) {
		long ans = 1;
		x = x % mod;
		if (x == 0)
			return 0;
		int i = 1;
		while (y > 0) {
			if ((y & 1) != 0)
				ans = (ans * x) % mod;
			y = y >> 1;
			x = (x * x) % mod;
		}
		return ans;
	}
	static long power(long x, long y)
	{
	    long res = 1;
	    while (y > 0)
	    {
	        if ((y & 1) != 0)
	            res = res * x;	  
	        y = y >> 1; 
	        x = x * x;  
	    }
	    return res;
	}
	public static void main(String[] args) throws Exception {
		FastReader sc = new FastReader();
		PrintWriter out = new PrintWriter(System.out);
		int t = sc.nextInt();
		outerloop:
			while(t-- > 0) {
                int n = sc.nextInt();
                TreeSet<Integer> ss = new TreeSet<>(Collections.reverseOrder());
                TreeMap<Integer, Integer> ssd = new TreeMap<>();
                int count = 0;
                for(int i = 1; i <= n; i++) ss.add(i);
                for(int i = 0; i < n; i++) {
                	int a = sc.nextInt();
                	if(ss.contains(a)) {
                		ss.remove(a);
                	}
                	else {
                		ssd.put((a + 1) / 2 - 1, ssd.getOrDefault((a + 1) / 2 - 1, 0) + 1);
                		count++;
                	}
                }
                for(int e: ss) {
                	if(ssd.higherKey(e - 1) == null) {
                		out.println(-1);
                		continue outerloop;
                	}
                	else {
                		Map.Entry<Integer, Integer> temp = ssd.higherEntry(e - 1);
                		ssd.remove(temp.getKey());
                		if(temp.getValue() - 1 >= 1)
                		ssd.put(temp.getKey(), temp.getValue() - 1);
                	}
                }
                out.println(count);
			}
		out.close();
	}
}