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.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;

/**
 * @author Mubtasim Shahriar
 */

public class Cr705A {

    public static void main(String[] args) {

        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader sc = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
		int t = sc.nextInt();
//        int t = 1;
        while (t-- != 0) {
            solver.solve(sc, out);
        }
        out.close();

    }

    static class Solver {
        public void solve(InputReader sc, PrintWriter out) {
            int n = sc.nextInt();
            int k = sc.nextInt();
            char[] arr = sc.next().toCharArray();
            if(n%k!=0) {
                out.println(-1);
                return;
            }
            int[][] cnt = new int[n][26];
            for(int i = 0; i < n; i++) {
                char now = arr[i];
                cnt[i][now-'a'] = 1;
                if(i>0) {
                    for(int j = 0; j < 26; j++) cnt[i][j] += cnt[i-1][j];
                }
            }
            if(isOk(cnt[n-1],k)) {
                out.println(new String(arr));
                return;
            }
            for(int i = n-1; i >= 0; i--) {
                int ncn = arr[i]-'a';
                int rest = n-i-1;
//                cnt[i][ncn]--;
                int[] prevCnt = new int[26];
                if(i>0) {
                    for(int l = 0; l < 26; l++) {
                        prevCnt[l] = cnt[i-1][l];
                    }
                }
                for(int j = ncn+1; j < 26; j++) {
                    prevCnt[j]++;
                    if(poss(prevCnt,rest,k)) {
                        int[] needs = new int[26];
                        for(int l = 0; l < 26; l++) {
                            needs[l] = getNeed(prevCnt[l],k);
                        }
                        int totalNeed = 0;
                        for(int l : needs) totalNeed+=l;
                        int moreNeed = rest-totalNeed;
                        char[] ans = new char[n];
                        for(int l = 0; l < i; l++) ans[l] = arr[l];
                        ans[i] = (char)('a'+j);
                        int l = i+1;
                        for(; l < n-totalNeed; l++) ans[l] = 'a';
                        for(int cidx = 0; cidx < needs.length; cidx++) {
                            if(needs[cidx]>0) {
                                while (needs[cidx]-->0) ans[l++] = (char)('a'+cidx);
                            }
                        }
                        out.println(new String(ans));
                        return;
                    }
                    prevCnt[j]--;
                }
            }

        }

        private boolean poss(int[] cnt, int rest, int k) {
            int[] needs = new int[26];
            for(int i = 0; i < 26; i++) {
                needs[i] = getNeed(cnt[i],k);
            }
            int totalNeed = 0;
            for(int i : needs) totalNeed+=i;
            return totalNeed<=rest;
        }

        private int getNeed(int cnt, int k) {
            if(cnt%k==0) return 0;
            return k-(cnt%k);
        }

        private boolean isOk(int[] ints, int k) {
            for(int i : ints) if(i%k!=0) return false;
            return true;
        }

    }

    static void sort(int[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
    }

    static void sort(long[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
    }

    static void sortDec(int[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
        int l = 0;
        int r = n - 1;
        while (l < r) {
            arr[l] ^= arr[r];
            arr[r] ^= arr[l];
            arr[l] ^= arr[r];
            l++;
            r--;
        }
    }

    static void sortDec(long[] arr) {
        Random rand = new Random();
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int idx = rand.nextInt(n);
            if (idx == i) continue;
            arr[i] ^= arr[idx];
            arr[idx] ^= arr[i];
            arr[i] ^= arr[idx];
        }
        Arrays.sort(arr);
        int l = 0;
        int r = n - 1;
        while (l < r) {
            arr[l] ^= arr[r];
            arr[r] ^= arr[l];
            arr[l] ^= arr[r];
            l++;
            r--;
        }
    }

    static class InputReader {
        private boolean finished = false;

        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int peek() {
            if (numChars == -1) {
                return -1;
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    return -1;
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                if (Character.isValidCodePoint(c)) {
                    res.appendCodePoint(c);
                }
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        private String readLine0() {
            StringBuilder buf = new StringBuilder();
            int c = read();
            while (c != '\n' && c != -1) {
                if (c != '\r') {
                    buf.appendCodePoint(c);
                }
                c = read();
            }
            return buf.toString();
        }

        public String readLine() {
            String s = readLine0();
            while (s.trim().length() == 0) {
                s = readLine0();
            }
            return s;
        }

        public String readLine(boolean ignoreEmptyLines) {
            if (ignoreEmptyLines) {
                return readLine();
            } else {
                return readLine0();
            }
        }

        public BigInteger readBigInteger() {
            try {
                return new BigInteger(nextString());
            } catch (NumberFormatException e) {
                throw new InputMismatchException();
            }
        }

        public char nextCharacter() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            return (char) c;
        }

        public double nextDouble() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.') {
                if (c == 'e' || c == 'E') {
                    return res * Math.pow(10, nextInt());
                }
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.') {
                c = read();
                double m = 1;
                while (!isSpaceChar(c)) {
                    if (c == 'e' || c == 'E') {
                        return res * Math.pow(10, nextInt());
                    }
                    if (c < '0' || c > '9') {
                        throw new InputMismatchException();
                    }
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }

        public boolean isExhausted() {
            int value;
            while (isSpaceChar(value = peek()) && value != -1) {
                read();
            }
            return value == -1;
        }

        public String next() {
            return nextString();
        }

        public SpaceCharFilter getFilter() {
            return filter;
        }

        public void setFilter(SpaceCharFilter filter) {
            this.filter = filter;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }

        public int[] nextIntArray(int n) {
            int[] array = new int[n];
            for (int i = 0; i < n; ++i) array[i] = nextInt();
            return array;
        }

        public int[] nextSortedIntArray(int n) {
            int array[] = nextIntArray(n);
            Arrays.sort(array);
            return array;
        }

        public int[] nextSumIntArray(int n) {
            int[] array = new int[n];
            array[0] = nextInt();
            for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
            return array;
        }

        public long[] nextLongArray(int n) {
            long[] array = new long[n];
            for (int i = 0; i < n; ++i) array[i] = nextLong();
            return array;
        }

        public long[] nextSumLongArray(int n) {
            long[] array = new long[n];
            array[0] = nextInt();
            for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
            return array;
        }

        public long[] nextSortedLongArray(int n) {
            long array[] = nextLongArray(n);
            Arrays.sort(array);
            return array;
        }
    }


}
