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.util.*;
public class P1493C {
    static InputReader in = new InputReader(System.in);
    static PrintWriter pw = new PrintWriter(System.out);
    static long mod = (long) (Math.pow(10, 9)) + 7;
    static HashMap<Integer, List<Integer>> adjList = new HashMap<>();
    static boolean[] visited;
    public static void main(String[] args) {
        int test = in.nextInt();
        while (test --> 0) {
            solve();
        }
        pw.close();
    }

    static int get(int x, int k) {
        return (k - x % k) % k;
    }

    static void solve() {
        int n = in.nextInt(), k = in.nextInt();
        int[] cnt = new int[26];
        String s = in.nextLine();
        for (int i = 0; i < s.length(); i++) {
            cnt[s.charAt(i) - 'a']++;
        }
        int sum = 0, flag = 1;
        for (int i = 0; i < 26; i++) {
            sum += get(cnt[i], k);
        }
        if (sum == 0) {
            pw.println(s);
            return;
        }

        if (n % k != 0) {
            pw.println(-1);
            return;
        }

        for (int i = n - 1; i >= 0; i--) {
            sum -= get(cnt[s.charAt(i) - 'a'], k);
            cnt[s.charAt(i) - 'a']--;
            sum += get(cnt[s.charAt(i) - 'a'], k);
            for (int j = s.charAt(i) - 'a' + 1; j < 26; j++) {
                int lastSum = sum;
                sum -= get(cnt[j], k);
                cnt[j]++;
                sum += get(cnt[j], k);
                if (i + sum + 1 <= n) {
                    for (int pos = 0; pos < i; pos++) {
                        pw.print(s.charAt(pos));
                    }
                    pw.print((char) ('a' + j));
                    StringBuilder add = new StringBuilder();
                    for (int w = 0; w < 26; w++) {
                        int f = get(cnt[w], k);
                        while (f > 0) {
                            f--;
                            add.append((char) ('a' + w));
                        }
                    }
                    while (add.length() + i + 1 < n) {
                        add.append("a");
                    }
                    char[] ans = add.toString().toCharArray();
                    Arrays.sort(ans);
                    for (char c : ans) {
                        pw.print(c);
                    }
                    pw.println();
                    return;
                }
                cnt[j]--;
                sum = lastSum;
            }
        }
    }

    static void rest(StringBuilder s, TreeMap<Character, Integer> cnt, int index, int k) {
        for (int i = index; i < s.length(); i++) {
            Character c = cnt.firstKey();
            s.replace(i, i + 1, String.valueOf(c));
            cnt.put(s.charAt(i), cnt.get(s.charAt(i)) - 1);
            if (cnt.get(s.charAt(i)) == 0) {
                cnt.remove(s.charAt(i));
            }
        }
    }

    static void ruffleSort(int[] a) {
        int n=a.length;
        Random r=new Random();
        for (int i=0; i<a.length; i++) {
            int oi=r.nextInt(n), temp=a[i];
            a[i]=a[oi];
            a[oi]=temp;
        }
        Arrays.sort(a);
    }

    public static List<Long> getFactors(long num) {
        List<Long> res = new ArrayList();
        res.add(num);

        for (long d = 2; d <= (long)Math.sqrt(num); d++) {
            if (num % d == 0) {
                res.add(d);
                if ((num / d) != d) {
                    res.add(num / d);
                }
            }
        }

        return res;
    }


    static long choose(long a, long b) {
        if(b > a - b)
            return choose(a, a - b);
        long m = 1;
        long d = 1;
        long i;
        for(i = 0; i < b; i++) {
            m *= (a - i);
            m %= mod;
            d *= (i + 1);
            d %= mod;
        }
        long ans = m * fast_pow(d, mod - 2) % mod;
        return ans;
    }


    static long fast_pow(long a, long b) {
        if(b == 0) return 1L;
        long val = fast_pow(a, b / 2);
        if(b % 2 == 0)
            return val * val % mod;
        else
            return val * val % mod * a % mod;
    }

    static void sort(long[] a) //check for long
    {
        ArrayList<Long> l=new ArrayList<>();
        for (long i:a) l.add(i);
        Collections.sort(l);
        for (int i=0; i<a.length; i++) a[i]=l.get(i);
    }

    static void sort(int[] a) {
        ArrayList<Integer> l=new ArrayList<>();
        for (int i:a) l.add(i);
        Collections.sort(l);
        for (int i=0; i<a.length; i++) a[i]=l.get(i);
    }


    static void addEdge(int u, int v) {
        adjList.putIfAbsent(u, new ArrayList<>());
        adjList.get(u).add(v);
    }

    static int gcd(int a, int b) {
        return b == 0 ? a : gcd(b, a % b);
    }

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

    static boolean[] sieve(int n) {
        boolean[] isPrime = new boolean[n + 1];
        isPrime[0] = false;
        isPrime[1] = false;
        for (int i = 2; i <= n; i++) {
            if (isPrime[i] && i * i <= n) {
                for (int j = i * i; j <= n; j += i) {
                    isPrime[i] = false;
                }
            }
        }
        return isPrime;
    }

    static boolean isPrime(int n) {
        for (int d = 2; d * d <= n; d++) {
            if (n % d == 0) {
                return false;
            }
        }
        return true;
    }

    //ternary search on a graph that is concave down
    static int high(int[] a) {
        int lo = 0, hi = a.length - 1;
        int error = 3;
        while (hi - lo > error) {
            int right = hi - (hi - lo) / 3;
            int left = lo + (hi - lo) / 3;
            if (a[left] < a[right]) {
                lo = left;
            } else {
                hi = right;
            }
        }
        //check for the lowest from a[l, h]
        int ans = lo;
        for (int i = lo; i <= hi; i++) {
            if (a[ans] < a[i]) {
                ans = i;
            }
        }
        return ans;
    }

    //ternary search on a concave up graph
    static int low(int[] a) {
        int lo = 0, hi = a.length - 1;
        int error = 3;
        while (hi - lo > error) {
            int right = hi - (hi - lo) / 3;
            int left = lo + (hi - lo) / 3;
            if (a[left] < a[right]) {
                hi = right;
            } else {
                lo = left;
            }
        }
        //check for the lowerst from a[l, h]
        int ans = lo;
        for (int i = lo; i <= hi; i++) {
            if (a[ans] > a[i]) {
                ans = i;
            }
        }
        return ans;
    }

    static boolean contains(int[] a, int key) {
        int ans = 0;
        int low = 0, high = a.length - 1;
        while (low <= high) {
            int mid = low + (high - low) / 2;
            int midVal = a[mid];

            if (midVal < key) {
                low = mid + 1;
            } else if (midVal > key) {
                high = mid - 1;
            }
            else if (midVal == key) {
                ans = 1;
                break;
            }
        }
        return ans == 1;
    }

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

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

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

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

    static class SegTree
    {
        long st[];
        public SegTree(long[] arr, int n) {
            int x = (int) (Math.ceil(Math.log(n) / Math.log(2)));
            int max_size = 2 * (int) Math.pow(2, x) - 1;
            st = new long[max_size];
            constructSTUtil(arr, 0, n - 1, 0);
        }

        int getMid(int s, int e) {
            return s + (e - s) / 2;
        }

        long getSumUtil(int ss, int se, int qs, int qe, int si) {
            if (qs <= ss && qe >= se)
                return st[si];
            if (se < qs || ss > qe)
                return 0;
            int mid = getMid(ss, se);
            return getSumUtil(ss, mid, qs, qe, 2 * si + 1) +
                    getSumUtil(mid + 1, se, qs, qe, 2 * si + 2);
        }

        void updateValueUtil(int ss, int se, int i, long diff, int si) {
            if (i < ss || i > se)
                return;
            st[si] = st[si] + diff;
            if (se != ss) {
                int mid = getMid(ss, se);
                updateValueUtil(ss, mid, i, diff, 2 * si + 1);
                updateValueUtil(mid + 1, se, i, diff, 2 * si + 2);
            }
        }

        void updateValue(long arr[], int n, int i, int new_val) {
            if (i < 0 || i > n - 1) {
                System.out.println("Invalid Input");
                return;
            }
            long diff = new_val - arr[i];
            arr[i] = new_val;
            updateValueUtil(0, n - 1, i, diff, 0);
        }

        long getSum(int n, int qs, int qe) {
            if (qs < 0 || qe > n - 1 || qs > qe) {
                System.out.println("Invalid Input");
                return -1;
            }
            return getSumUtil(0, n - 1, qs, qe, 0);
        }

        long constructSTUtil(long arr[], int ss, int se, int si) {
            if (ss == se) {
                st[si] = arr[ss];
                return arr[ss];
            }
            int mid = getMid(ss, se);
            st[si] = constructSTUtil(arr, ss, mid, si * 2 + 1) +
                    constructSTUtil(arr, mid + 1, se, si * 2 + 2);
            return st[si];
        }
    }


    static class UnionFind {
        // Number of connected components
        private int count;
        // Store a tree
        private int[] parent;
        // Record the "weight" of the tree
        private int[] size;

        public UnionFind(int n) {
            this.count = n;
            parent = new int[n];
            size = new int[n];
            for (int i = 0; i < n; i++) {
                parent[i] = i;
                size[i] = 1;
            }
        }

        public void union(int p, int q) {
            int rootP = find(p);
            int rootQ = find(q);
            if (rootP == rootQ)
                return;

            // The small tree is more balanced under the big tree
            if (size[rootP] > size[rootQ]) {
                parent[rootQ] = rootP;
                size[rootP] += size[rootQ];
            } else {
                parent[rootP] = rootQ;
                size[rootQ] += size[rootP];
            }
            count--;
        }

        public boolean connected(int p, int q) {
            int rootP = find(p);
            int rootQ = find(q);
            return rootP == rootQ;
        }

        private int find(int x) {
            while (parent[x] != x) {
                // Path compression
                parent[x] = parent[parent[x]];
                x = parent[x];
            }
            return x;
        }

        public int count() {
            return count;
        }
    }
    static class InputReader {

        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;

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

        public int read() {
            if (snumChars == -1)
                throw new InputMismatchException();
            if (curChar >= snumChars) {
                curChar = 0;
                try {
                    snumChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (snumChars <= 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 {
                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 {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

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

        public static int[] shuffle(int[] a, Random gen)
        { for(int i = 0, n = a.length;i < n;i++)
        { int ind = gen.nextInt(n-i)+i;
            int d = a[i];
            a[i] = a[ind];
            a[ind] = d;

        }
            return a;
        }


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

        public String nextLine() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        }

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

        private boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }
    }
}
