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.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.util.*;
import java.util.concurrent.LinkedBlockingDeque;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;


// graph, dfs,bfs, get connected components,iscycle, isbipartite, dfs on trees



public class scratch_25 {
    static class Graph{

        public static class Vertex{
            HashMap<Integer,Integer> nb= new HashMap<>();     // for neighbours of each vertex
        }

        public static HashMap<Integer,Vertex> vt;   // for vertices(all)

        public Graph(){
            vt= new HashMap<>();
        }

        public static int numVer(){
            return vt.size();
        }

        public static boolean contVer(int ver){
            return vt.containsKey(ver);
        }

        public static void addVer(int ver){
            Vertex v= new Vertex();
            vt.put(ver,v);
        }






        public static void addEdge(int ver1, int ver2, int weight){
            if(!vt.containsKey(ver1) || !vt.containsKey(ver2)){
                return;
            }
            Vertex v1= vt.get(ver1);
            Vertex v2= vt.get(ver2);
            v1.nb.put(ver2,weight);                                 // if previously there is an edge, then this replaces that edge
            v2.nb.put(ver1,weight);
        }

        public static void delEdge(int ver1, int ver2){

            if(!vt.containsKey(ver1) || !vt.containsKey(ver2)){
                return;
            }
            vt.get(ver1).nb.remove(ver2);
            vt.get(ver2).nb.remove(ver1);
        }
        public static void delVer(int ver){
            if(!vt.containsKey(ver)){
                return;
            }
            Vertex v1= vt.get(ver);
            ArrayList<Integer> arr= new ArrayList<>(v1.nb.keySet());
            for (int i = 0; i <arr.size() ; i++) {
                int s= arr.get(i);
                vt.get(s).nb.remove(ver);
            }
            vt.remove(ver);
        }
        static boolean done[];
        static int parent[];
        static ArrayList<Integer>vals= new ArrayList<>();


        public static boolean isCycle(int i){
            Stack<Integer>stk= new Stack<>();

            stk.push(i);
            while(!stk.isEmpty()){
                int x= stk.pop();
                vals.add(x);
                //   System.out.print("current="+x+" stackinit="+stk);
                if(!done[x]){
                    done[x]=true;
                }
                else if(done[x] ){
                    return true;
                }

                ArrayList<Integer>ar= new ArrayList<>(vt.get(x).nb.keySet());
                for (int j = 0; j <ar.size() ; j++) {
                    if(parent[x]!=ar.get(j)){
                        parent[ar.get(j)]=x;
                        stk.push(ar.get(j));
                    }
                }
                // System.out.println(" stackfin="+stk);
            }
            return false;
        }
        static int[]level;
        static int[] curr;
        static int[] fin;

        public static void dfs(int src){
            done[src]=true;
            level[src]=0;
            Queue<Integer>q= new LinkedList<>();
            q.add(src);
            while(!q.isEmpty()){
                int x= q.poll();
                ArrayList<Integer>arr= new ArrayList<>(vt.get(x).nb.keySet());
                for (int i = 0; i <arr.size() ; i++) {
                    int v= arr.get(i);
                    if(!done[v]){
                        level[v]=level[x]+1;
                        done[v]=true;
                        q.offer(v);
                    }
                }
            }
        }
        static int oc[];
        static int ec[];


        public static void dfs1(int src){
            Queue<Integer>q= new LinkedList<>();
            q.add(src);
            done[src]= true;
            //    int count=0;
            while(!q.isEmpty()){

                int x= q.poll();
                //   System.out.println("x="+x);
                int even= ec[x];
                int odd= oc[x];
                if(level[x]%2==0){
                    int val= (curr[x]+even)%2;
                    if(val!=fin[x]){
                        //  System.out.println("bc");
                        even++;
                        vals.add(x);
                    }
                }
                else{
                    int val= (curr[x]+odd)%2;
                    if(val!=fin[x]){
                        //   System.out.println("bc");
                        odd++;
                        vals.add(x);
                    }

                }
                ArrayList<Integer>arr= new ArrayList<>(vt.get(x).nb.keySet());
                //   System.out.println(arr);
                for (int i = 0; i <arr.size() ; i++) {
                    int v= arr.get(i);
                    if(!done[v]){
                        done[v]=true;
                        oc[v]=odd;
                        ec[v]=even;
                        q.add(v);
                    }
                }
            }

        }

        static long popu[];
        static long happy[];
        static long count[]; // total people crossing that pos
        static long sum[]; // total sum of happy people including that.


        public static void bfs(int x){
            done[x]=true;
            long total= popu[x];
//            long smile= happy[x];
            ArrayList<Integer>nbrs= new ArrayList<>(vt.get(x).nb.keySet());
            for (int i = 0; i <nbrs.size() ; i++) {
                int r= nbrs.get(i);
                if(!done[r]){
                    bfs(r);
                    total+=count[r];
//                    smile+=sum[r];
                }
            }
            count[x]=total;
//            sum[x]=smile;
        }


        public static void bfs1(int x){
            done[x]=true;
//            long total= popu[x];
            long smile= 0;
            ArrayList<Integer>nbrs= new ArrayList<>(vt.get(x).nb.keySet());
            for (int i = 0; i <nbrs.size() ; i++) {
                int r= nbrs.get(i);
                if(!done[r]){
                    bfs1(r);
//                    total+=count[r];
                    smile+=happy[r];
                }
            }
//            count[x]=total;
            sum[x]=smile;
        }


    }




    static class Reader {
        static BufferedReader reader;
        static StringTokenizer tokenizer;

        /**
         * call this method to initialize reader for InputStream
         */
        static void init(InputStream input) {
            reader = new BufferedReader(
                    new InputStreamReader(input));
            tokenizer = new StringTokenizer("");
        }

        /**
         * get next word
         */
        static String next() throws IOException {
            while (!tokenizer.hasMoreTokens()) {
                //TODO add check for eof if necessary
                tokenizer = new StringTokenizer(
                        reader.readLine());
            }
            return tokenizer.nextToken();
        }

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

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

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


    static class Pair implements Comparable<Pair> {
        long x;
        long y;
        long z;

        public Pair(long x, long y,long z) {
            this.x = x;
            this.y = y;
            this.z=z;
        }


        @Override
        public String toString() {
            return x + " " + y;
        }

        @Override
        public int compareTo(Pair o) {
            if(this.x >o.x){
                return 1;
            }
            else if(this.x==o.x){
                return 0;
            }
            else{
                return -1;
            }
        }
    }
    static class Pair1 implements Comparable<Pair1> {
        double d1;
        double d2;


        public Pair1(double d1, double d2) {
            this.d1 = d1;
            this.d2 =d2;
//            this.z=z;
        }


        @Override
        public String toString() {
            return d1 + " " + d2;
        }

        @Override
        public int compareTo(Pair1 o) {
            if(this.d1 >o.d1){
                return 1;
            }
            else if(this.d1==o.d1){
                return 0;
            }
            else{
                return -1;
            }
        }
    }




    // After writing solution, quick scan for:
    //   array out of bounds
    //   special cases e.g. n=1?
    //
    // Big numbers arithmetic bugs:
    //   int overflow
    //   sorting, or taking max, or negative after MOD
//    static long mod= (long)1e9+7;

    public static void main(String[] args)  throws IOException {
        Reader.init(System.in);
        BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
//        System.out.println('z'-'a');
        int t= Reader.nextInt();
        for (int tt = 0; tt <t ; tt++) {
            int n= Reader.nextInt();
            int k= Reader.nextInt();
            String s= Reader.next();
            if(n%k!=0){
                out.append(-1+"\n");
            }
            else{

                int count[]= new int[26];
                for (int i = 0; i <n ; i++) {
                    char x= s.charAt(i);
                    count[x-'a']++;
                }

                int sum=0;
                for (int i = 0; i <26 ; i++) {
                    int f= count[i];
                    int rem= (int)ceil_div(f,k)*k-f;
//                    System.out.println(i+" "+rem);
                    sum+=rem;
                }

                if(sum==0){
                    out.append(s+"\n");
                }
                else{

                    boolean done=false;
                    for (int i = n-1; i >=0 ; i--) {

                        char x= s.charAt(i);
                        int f= count[x-'a'];
                        int rem= (int)ceil_div(f,k)*k-f;
                        sum-=rem;
                        f--;
                        count[x-'a']=f;
                        rem= (int)ceil_div(f,k)*k-f;
                        sum+=rem;

                        for (int j = x-'a'+1; j <= 'z'-'a' ; j++) {
                            int sum1=sum;
                            int g= count[j];
                            int re= (int)ceil_div(g,k)*k-g;
                            sum-=re;
                            g++;
                            count[j]=g;
                            re=  (int)ceil_div(g,k)*k-g;
                            sum+=re;

                            if(sum<=n-i-1) {

                                String preans = s.substring(0, i);
                                char z= (char)(j+'a');
                                preans+=z;

                                ArrayList<Character>more= new ArrayList<>();

                                for (int l = 0; l <26 ; l++) {
                                   int h= (int)ceil_div(count[l],k)*k-count[l];

                                    for (int m = 0; m <h ; m++) {
                                        more.add((char)(l+'a'));
                                    }
                                }

                                int mo= n-1-i-more.size();
                                for (int l = 0; l <mo ; l++) {
                                    more.add('a');
                                }
                                Collections.sort(more);

                              out.append(preans);


                                for (int l = 0; l <more.size() ; l++) {
                                    out.append(more.get(l));
                                }
                                out.append("\n");
                                done=true;
                                break;

                            }


                            else{
                               sum=sum1;
                               count[j]--;
                            }


                        }
                        if(done){
                            break;
                        }
                    }
                }
            }
        }
        out.flush();
        out.close();

    }




    public static int localMinUtil(int[] arr, int low,
                                   int high, int n)
    {


        // Find index of middle element
        int mid = low + (high - low) / 2;

        // Compare middle element with its neighbours
        // (if neighbours exist)
        if(mid == 0 || arr[mid - 1] > arr[mid] && mid == n - 1 ||
                arr[mid] < arr[mid + 1])
            return mid;

            // If middle element is not minima and its left
            // neighbour is smaller than it, then left half
            // must have a local minima.
        else if(mid > 0 && arr[mid - 1] < arr[mid])
            return localMinUtil(arr, low, mid - 1, n);

        // If middle element is not minima and its right
        // neighbour is smaller than it, then right half
        // must have a local minima.
        return localMinUtil(arr, mid + 1, high, n);
    }

    // A wrapper over recursive function localMinUtil()
    public static int localMin(int[] arr, int n)
    {
        return localMinUtil(arr, 0, n - 1, n);
    }








    public static String convert(String s,int n){
        if(s.length()==n){
            return s;
        }
        else{
            int x= s.length();
            int v=n-x;
            String str="";
            for (int i = 0; i <v ; i++) {
                str+='0';
            }
            str+=s;
            return str;

        }
    }
    public static int lower(int arr[],int key){
        int low = 0;
        int high = arr.length-1;
        while(low < high){
            int mid = low + (high - low)/2;
            if(arr[mid] >= key){
                high = mid;
            }
            else{
                low = mid+1;
            }
        }
        return low;
    }

    public static int upper(int arr[],int key){
        int low = 0;
        int high = arr.length-1;
        while(low < high){
            int mid = low + (high - low+1)/2;
            if(arr[mid] <= key){
                low = mid;
            }
            else{
                high = mid-1;
            }
        }
        return low;
    }





    static long modExp(long a, long b, long mod) {
        //System.out.println("a is " + a + " and b is " + b);
        if (a==1) return 1;
        long ans = 1;
        while (b!=0) {
            if (b%2==1) {
                ans = (ans*a)%mod;
            }
            a = (a*a)%mod;
            b/=2;
        }
        return ans;
    }


    public static long modmul(long a, long b, long mod) {
        return b == 0 ? 0 : ((modmul(a, b >> 1, mod) << 1) % mod + a * (b & 1)) % mod;
    }

    static long sum(long n){
        //   System.out.println("lol="+ (n*(n-1))/2);
        return (n*(n+1))/2;
    }






    public static ArrayList<Integer> Sieve(int n) {
        boolean arr[]= new boolean [n+1];
        Arrays.fill(arr,true);
        arr[0]=false;
        arr[1]=false;
        for (int i = 2; i*i <=n ; i++) {
            if(arr[i]){
                for (int j = 2; j <=n/i ; j++) {
                    int u= i*j;
                    arr[u]=false;
                }}
        }
        ArrayList<Integer> ans= new ArrayList<>();
        for (int i = 0; i <n+1 ; i++) {
            if(arr[i]){
                ans.add(i);
            }
        }
        return ans;
    }




    static long power( long x, long y, long p)
    {

        long res = 1;


        x = x % p;

        if (x == 0) return 0;

        while (y > 0)
        {

            if((y & 1)==1)
                res = (res * x) % p;


            y = y >> 1;
            x = (x * x) % p;
        }
        return res;
    }

    public static long ceil_div(long a, long b){
        return (a+b-1)/b;
    }

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

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

}