You are given a string s consisting of lowercase English letters and a number k. Let's call a string consisting of lowercase English letters beautiful if the number of occurrences of each letter in that string is divisible by k. You are asked to find the lexicographically smallest beautiful string of length n, which is lexicographically greater or equal to string s. If such a string does not exist, output -1.

A string a is lexicographically smaller than a string b if and only if one of the following holds: 

  * a is a prefix of b, but a ≠ b; 
  * in the first position where a and b differ, the string a has a letter that appears earlier in the alphabet than the corresponding letter in b. 

Input

The first line contains a single integer T (1 ≤ T ≤ 10 000) — the number of test cases.

The next 2 ⋅ T lines contain the description of test cases. The description of each test case consists of two lines.

The first line of the description contains two integers n and k (1 ≤ k ≤ n ≤ 10^5) — the length of string s and number k respectively.

The second line contains string s consisting of lowercase English letters.

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

Output

For each test case output in a separate line lexicographically smallest beautiful string of length n, which is greater or equal to string s, or -1 if such a string does not exist.

Example

Input


4
4 2
abcd
3 1
abc
4 3
aaaa
9 3
abaabaaaa


Output


acac
abc
-1
abaabaaab

Note

In the first test case "acac" is greater than or equal to s, and each letter appears 2 or 0 times in it, so it is beautiful.

In the second test case each letter appears 0 or 1 times in s, so s itself is the answer.

We can show that there is no suitable string in the third test case.

In the fourth test case each letter appears 0, 3, or 6 times in "abaabaaab". All these integers are divisible by 3.
import java.util.ArrayList;
import java.util.Collections;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
import java.util.Arrays;
import java.util.Random;
import java.io.FileWriter;
import java.io.PrintWriter;
/*
    Solution Created: 18:11:55 06/03/2021
    Custom Competitive programming helper.
*/

public class Main {
	
	public static void solve() {
		int n = in.nextInt(), k = in.nextInt();
		char[] a = in.nca();
		if(n%k!=0){
			out.println(-1);
			return;
		}
		int[][] freq = new int[n][26];
		for(int i = 0; i<n; i++){
			freq[i][a[i]-'a']++;
			if(i>0)
			for(int j = 0; j<26; j++) freq[i][j] += freq[i-1][j];
		}
		boolean allValid = true;
		for(int i = 0; i<26; i++) {
			allValid&= freq[n-1][i]%k==0;
		}
		if(allValid){
			for(char c : a) out.print(c);
			out.println();
			return;
		}
		for(int i = n-1; i>=0; i--){
			for(int j = a[i]+1; j<='z'; j++){
				int[] have = new int[26];
				if(i>0)
				for(int l = 0; l<26; l++) have[l] += freq[i-1][l];
				have[j-'a']++;
				int minNeed = 0;
				int[] needI = new int[26];
				for(int l = 0; l<26; l++){
					if(have[l]%k==0) continue;
					int fit = have[l]/k;
					minNeed+= (fit+1)*k-have[l];
					needI[l] = (fit+1)*k-have[l];
				}
				int nextSpace = n-i-1;
				if(minNeed>nextSpace) continue;
				ArrayList<Character> nextMoves = new ArrayList<>();
				for(int l = 0; l<26; l++){
					for(int v = 0; v<needI[l]; v++){
						nextMoves.add((char)(l+'a'));
						nextSpace--;
					}
				}
				if(nextSpace%k!=0) continue;
				while(nextSpace-->0) nextMoves.add((char)('a'));
				
				Collections.sort(nextMoves);
				for(int l = 0; l<i; l++) out.print(a[l]);
				out.print((char)(j));
				for(Character c : nextMoves) out.print(c);
				out.println();
				return;
			}
		}
		out.println(-1);
	}
	
	public static void main(String[] args) {
		in = new Reader();
		out = new Writer();
		int t = in.nextInt();
		while(t-->0) solve();
		out.exit();
	}
	static Reader in; static Writer out;

static class Reader {
	static BufferedReader br;
	static StringTokenizer st;
	
	public Reader() {
		this.br = new BufferedReader(new InputStreamReader(System.in));
	}
	
	public Reader(String f){
		try {
			this.br = new BufferedReader(new FileReader(f));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++) a[i] = nextInt();
		return a;
	}

	public double[] nd(int n) {
		double[] a = new double[n];
		for (int i = 0; i < n; i++) a[i] = nextDouble();
		return a;
	}
	
	public long[] nl(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++) a[i] = nextLong();
		return a;
	}

	public char[] nca() {
		return next().toCharArray();
	}

	public String[] ns(int n) {
		String[] a = new String[n];
		for (int i = 0; i < n; i++) a[i] = next();
		return a;
	}

	public int nextInt() {
		ensureNext();
		return Integer.parseInt(st.nextToken());
	}

	public double nextDouble() {
		ensureNext();
		return Double.parseDouble(st.nextToken());
	}

	public Long nextLong() {
		ensureNext();
		return Long.parseLong(st.nextToken());
	}

	public String next() {
		ensureNext();
		return st.nextToken();
	}
	
	public String nextLine() {
		try {
			return br.readLine();
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}
	
	private void ensureNext() {
		if (st == null || !st.hasMoreTokens()) {
			try {
				st = new StringTokenizer(br.readLine());
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}

static class Util{
		private static Random random = new Random();
		static long[] fact;
		
		public static void initFactorial(int n, long mod) {
			fact = new long[n+1];
			fact[0] = 1;
			for (int i = 1; i < n+1; i++) fact[i] = (fact[i - 1] * i) % mod;
		}
		
		public static long modInverse(long a, long MOD) {
			long[] gcdE = gcdExtended(a, MOD);
			if (gcdE[0] != 1) return -1; // Inverted doesn't exist
			long x = gcdE[1];
			return (x % MOD + MOD) % MOD;
		}
		
		public static long[] gcdExtended(long p, long q) {
			if (q == 0) return new long[] { p, 1, 0 };
			long[] vals = gcdExtended(q, p % q);
			long tmp = vals[2];
			vals[2] = vals[1] - (p / q) * vals[2];
			vals[1] = tmp;
			return vals;
		}
		
		public static long nCr(int n, int r, long MOD) {
			if (r == 0) return 1;
			return (fact[n] * modInverse(fact[r], MOD) % MOD * modInverse(fact[n - r], MOD) % MOD) % MOD;
		}
		
		public static long nCr(int n, int r) {
			return (fact[n]/fact[r])/fact[n-r];
		}
		
		public static long nPr(int n, int r, long MOD) {
			if (r == 0) return 1;
			return (fact[n] * modInverse(fact[n - r], MOD) % MOD) % MOD;
		}
		public static long nPr(int n, int r) {
			return fact[n]/fact[n-r];
		}
		
		public static boolean isPrime(int n) { 
	        if (n <= 1) return false; 
	        if (n <= 3) return true; 
	        if (n % 2 == 0 || n % 3 == 0) return false; 
	        for (int i = 5; i * i <= n; i = i + 6) 
	            if (n % i == 0 || n % (i + 2) == 0) 
	            return false; 
	        return true; 
	    }
		
	    public static boolean[] getSieve(int n) {
	        boolean[] isPrime = new boolean[n+1];
	        for (int i = 2; i <= n; i++) isPrime[i] = true;
	        for (int i = 2; i*i <= n; i++) if (isPrime[i]) 
	                for (int j = i; i*j <= n; j++) isPrime[i*j] = false;
	        return isPrime;
	    }
	    
	    public static int gcd(int a, int b) { 
	    	int tmp = 0;
	    	while(b != 0) {
	    		tmp = b;
	    		b = a%b;
	    		a = tmp;
	    	}
	    	return a;
	    }
	    
	    public static long gcd(long a, long b) { 
	    	long tmp = 0;
	    	while(b != 0) {
	    		tmp = b;
	    		b = a%b;
	    		a = tmp;
	    	}
	    	return a;
	    }
	    
	    public static int random(int min, int max) {
	    	return random.nextInt(max-min+1)+min;
	    }
	    
		public static void dbg(Object... o) { 
			System.out.println(Arrays.deepToString(o)); 
		}
		
		public static void reverse(int[] s, int l , int r) {
			for(int i = l; i<=(l+r)/2; i++) {
				int tmp = s[i];
				s[i] = s[r+l-i];
				s[r+l-i] = tmp;
			}
	    }
		
		public static void reverse(int[] s) {
			reverse(s, 0, s.length-1);
	    }
		
		public static void reverse(long[] s, int l , int r) {
			for(int i = l; i<=(l+r)/2; i++) {
				long tmp = s[i];
				s[i] = s[r+l-i];
				s[r+l-i] = tmp;
			}
	    }
		
		public static void reverse(long[] s) {
			reverse(s, 0, s.length-1);
	    }
		
		public static void reverse(float[] s, int l , int r) {
			for(int i = l; i<=(l+r)/2; i++) {
				float tmp = s[i];
				s[i] = s[r+l-i];
				s[r+l-i] = tmp;
			}
	    }
		
		public static void reverse(float[] s) {
			reverse(s, 0, s.length-1);
	    }
		
		public static void reverse(double[] s, int l , int r) {
			for(int i = l; i<=(l+r)/2; i++) {
				double tmp = s[i];
				s[i] = s[r+l-i];
				s[r+l-i] = tmp;
			}
	    }
		
		public static void reverse(double[] s) {
			reverse(s, 0, s.length-1);
	    }
		
		public static void reverse(char[] s, int l , int r) {
			for(int i = l; i<=(l+r)/2; i++) {
				char tmp = s[i];
				s[i] = s[r+l-i];
				s[r+l-i] = tmp;
			}
	    }
		
		public static void reverse(char[] s) {
			reverse(s, 0, s.length-1);
	    }
		
		public static <T> void reverse(T[] s, int l , int r) {
			for(int i = l; i<=(l+r)/2; i++) {
				T tmp = s[i];
				s[i] = s[r+l-i];
				s[r+l-i] = tmp;
			}
	    }
		
		public static <T> void reverse(T[] s) {
			reverse(s, 0, s.length-1);
	    }
		
		public static void shuffle(int[] s) {
	        for (int i = 0; i < s.length; ++i) {
	            int j = random.nextInt(i + 1);
	            int t = s[i];
	            s[i] = s[j];
	            s[j] = t;
	        }
	    }
		
	    public static void shuffle(long[] s) {
	        for (int i = 0; i < s.length; ++i) {
	            int j = random.nextInt(i + 1);
	            long t = s[i];
	            s[i] = s[j];
	            s[j] = t;
	        }
	    }
	    
	    public static void shuffle(float[] s) {
	        for (int i = 0; i < s.length; ++i) {
	            int j = random.nextInt(i + 1);
	            float t = s[i];
	            s[i] = s[j];
	            s[j] = t;
	        }
	    }
	    
	    public static void shuffle(double[] s) {
	        for (int i = 0; i < s.length; ++i) {
	            int j = random.nextInt(i + 1);
	            double t = s[i];
	            s[i] = s[j];
	            s[j] = t;
	        }
	    }
	    
	    public static void shuffle(char[] s) {
	        for (int i = 0; i < s.length; ++i) {
	            int j = random.nextInt(i + 1);
	            char t = s[i];
	            s[i] = s[j];
	            s[j] = t;
	        }
	    }
	    
	    public static <T> void shuffle(T[] s) {
	        for (int i = 0; i < s.length; ++i) {
	            int j = random.nextInt(i + 1);
	            T t = s[i];
	            s[i] = s[j];
	            s[j] = t;
	        }
	    }
	    
		public static void sortArray(int[] a) {
	        shuffle(a);
	        Arrays.sort(a);
	    }
		
		public static void sortArray(long[] a) {
			shuffle(a);
	        Arrays.sort(a);
	    }
		
		public static void sortArray(float[] a) {
			shuffle(a);
	        Arrays.sort(a);
	    }
		
		public static void sortArray(double[] a) {
			shuffle(a);
	        Arrays.sort(a);
	    }
		
		public static void sortArray(char[] a) {
			shuffle(a);
	        Arrays.sort(a);
	    }
		
		public static <T extends Comparable<T>> void sortArray(T[] a) {
	        Arrays.sort(a);
	    }
	}

static class Writer {
	private PrintWriter pw;
	public Writer(){
		pw = new PrintWriter(System.out);
	}
	
	public Writer(String f){
		try {
			pw = new PrintWriter(new FileWriter(f));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public void printArray(int[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
	}
	
	public void printlnArray(int[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
		pw.println();
	}
	
	public void printArray(long[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
	}
	
	public void printlnArray(long[] a) {
		for(int i = 0; i<a.length; i++) print(a[i]+" ");
		pw.println();
	}
	
	public void print(Object o) {
		pw.print(o.toString());
	}
	
	public void println(Object o) {
		pw.println(o.toString());
	}
	
	public void println() {
		pw.println();
	}
	
	public void flush() {
		pw.flush();
	}
	public void exit() {
		pw.close();
	}
}
}
