You are given a non-decreasing array of non-negative integers a_1, a_2, …, a_n. Also you are given a positive integer k.

You want to find m non-decreasing arrays of non-negative integers b_1, b_2, …, b_m, such that:

  * The size of b_i is equal to n for all 1 ≤ i ≤ m. 
  * For all 1 ≤ j ≤ n, a_j = b_{1, j} + b_{2, j} + … + b_{m, j}. In the other word, array a is the sum of arrays b_i. 
  * The number of different elements in the array b_i is at most k for all 1 ≤ i ≤ m. 



Find the minimum possible value of m, or report that there is no possible m.

Input

The first line contains one integer t (1 ≤ t ≤ 100): the number of test cases.

The first line of each test case contains two integers n, k (1 ≤ n ≤ 100, 1 ≤ k ≤ n).

The second line contains n integers a_1, a_2, …, a_n (0 ≤ a_1 ≤ a_2 ≤ … ≤ a_n ≤ 100, a_n > 0).

Output

For each test case print a single integer: the minimum possible value of m. If there is no such m, print -1.

Example

Input


6
4 1
0 0 0 1
3 1
3 3 3
11 3
0 1 2 2 3 3 3 4 4 4 4
5 3
1 2 3 4 5
9 4
2 2 3 5 7 11 13 13 17
10 7
0 1 1 2 3 3 4 5 5 6


Output


-1
1
2
2
2
1

Note

In the first test case, there is no possible m, because all elements of all arrays should be equal to 0. But in this case, it is impossible to get a_4 = 1 as the sum of zeros.

In the second test case, we can take b_1 = [3, 3, 3]. 1 is the smallest possible value of m.

In the third test case, we can take b_1 = [0, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2] and b_2 = [0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2]. It's easy to see, that a_i = b_{1, i} + b_{2, i} for all i and the number of different elements in b_1 and in b_2 is equal to 3 (so it is at most 3). It can be proven that 2 is the smallest possible value of m.
/*
                       _oo0oo_
                      o8888888o
                      88" . "88
                      (| -_- |)
                      0\  =  /0
                    ___/`---'\___
                  .' \\|     |// '.
                 / \\|||  :  |||// \
                / _||||| -:- |||||- \
               |   | \\\  -  /// |   |
               | \_|  ''\---/''  |_/ |
               \  .-\__  '-'  ___/-. /
             ___'. .'  /--.--\  `. .'___
          ."" '<  `.___\_<|>_/___.' >' "".
         | | :  `- \`.;`\ _ /`;.`/ - ` : | |
         \  \ `_.   \_ __\ /__ _/   .-` /  /
     =====`-.____`.___ \_____/___.-`___.-'=====
                       `=---='
 
*/
import java.util.function.Consumer;
import java.util.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.text.DecimalFormat;
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 boolean isBracketSequence(String s, int a, int b) {
		Stack<Character> ss = new Stack<>();
		boolean hachu = true;
		for(int i = a; i <= b; i++) {
			if(s.charAt(i) == ')' && ss.isEmpty()) {hachu = false; break;}
			if(s.charAt(i) == '(') ss.add('(');
			else ss.pop();
		}
		return ss.empty() && hachu;
	}
	static String reverseOfString(String a) {
		StringBuilder ssd = new StringBuilder();
		for(int i = a.length() - 1; i >= 0; i--) {
			ssd.append(a.charAt(i));
		}
		return ssd.toString();
	}
	static char[] reverseOfChar(char a[]) {
		char b[] = new char[a.length];
		int j = 0;
		for(int i = a.length - 1; i >= 0; i--) {
			b[i] = a[j];
			j++;
		}
		return b;
	}
	static boolean isPalindrome(char a[]) {
		boolean hachu = true;
		for(int i = 0; i <= a.length / 2; i++) {
			if(a[i] != a[a.length - 1 - i]) {
				hachu = false;
				break;
			}
		}
		return hachu;
	} 
	static long gcd(long a, long b)
	{
	    if (b == 0)
	        return a;
	    return gcd(b, a % b);
	     
	}
	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 ans = 1;
	    if (x == 0)
	      return 0; 
	    int i = 1;
	    while (y > 0){
	      if ((y & 1) != 0)
	        ans = (ans * x);
	      y = y >> 1; 
	      x = (x * x);
	    }
	    return ans;
	  }
	static boolean check(String a) {
		boolean hachu = true;
		for(int i = 0; i < a.length(); i++) {
			if(a.charAt(0) != a.charAt(i)) {hachu = false; break;}
		}
		return hachu;
	}
	static boolean checkArray(int x, int arr[]) {
		boolean hachu = true;
		for(int i = 0; i < arr.length; i++) {
			if(x != arr[i]) {hachu = false; break;}
		}
		return hachu;
	}
	 public static class Pair implements Comparable<Pair> {
	        public  int index;
	        public  int value;
	 
	        public Pair(int index, int value) {
	            this.index = index;
	            this.value = value;
	        }
	        @Override
	        public int compareTo(Pair other) {
	            //multiplied to -1 as the author need descending sort order
	            return   -1 * Integer.valueOf(this.index).compareTo(other.index);
	        }
	 }
	 static boolean equalString(int i, int j, int arr[], String b) {
		 int brr[] = new int[26];
		 for(int k = i; k <= j; k++) brr[b.charAt(k) - 'a']++;
		 for(int k = 0; k < 26; k++) {
			 if(arr[k] != brr[k]) return false;
		 }
		 return true;
	 }
	 static boolean cequalArray(String a, String b) {
		  int count[] = new int[26];
		  int count1[] = new int[26];
		  for(int i = 0; i < a.length(); i++) count[a.charAt(i) - 'a']++;
		  for(int i = 0; i < a.length(); i++) count1[b.charAt(i) - 'a']++;
		  for(int i = 0; i < 26; i++) if(count[i] != count1[i]) return false;
		  return true;
	 }
	 static boolean isPrime(long d) {
		 if(d == 1) return true;
		 for(int i = 2; i <= (long)Math.sqrt(d); i++) {
			 if(d % i == 0) return false;
		 }
		 return true;
	 }
	 static String decimalTob(int n, int b, String g) {
		  int z = n % b;
		  g = String.valueOf(z) + g;
		  n /= b;
		  if(n > 0) {
			  g = decimalTob(n, b, g);
		  }
		  return g;
	 }
		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();
                  int k = sc.nextInt();
                  int arr[] = new int[n];
                  TreeSet<Integer> ss = new TreeSet<>();
                  for(int i = 0; i < n; i++) ss.add(arr[i] = sc.nextInt());
                  int temp = 0;
                  int count = 0;
                  while(ss.size() != 1) {
                	  if(temp == ss.size()) break;
                       temp = ss.size();
                       TreeSet<Integer> ssd = new TreeSet<>();
                       for(int i = 0; i < n; i++) {
                    	   ssd.add(arr[i]);
                    	   if(ssd.size() <= k) arr[i] = 0;
                    	   else break;
                       }
                       ss.clear();
                       for(int i = 0; i < n; i++) ss.add(arr[i]);
                       count++;
                  }
                  if(ss.size() == 1 && arr[0] != 0) count++;
                  if(ss.size() == 1) out.println(count);
                  else out.println(-1);
            	  }
                 out.close();
			}
		}