n people gathered to hold a jury meeting of the upcoming competition, the i-th member of the jury came up with a_i tasks, which they want to share with each other.

First, the jury decides on the order which they will follow while describing the tasks. Let that be a permutation p of numbers from 1 to n (an array of size n where each integer from 1 to n occurs exactly once).

Then the discussion goes as follows:

  * If a jury member p_1 has some tasks left to tell, then they tell one task to others. Otherwise, they are skipped. 
  * If a jury member p_2 has some tasks left to tell, then they tell one task to others. Otherwise, they are skipped. 
  * ... 
  * If a jury member p_n has some tasks left to tell, then they tell one task to others. Otherwise, they are skipped. 
  * If there are still members with tasks left, then the process repeats from the start. Otherwise, the discussion ends. 



A permutation p is nice if none of the jury members tell two or more of their own tasks in a row. 

Count the number of nice permutations. The answer may be really large, so print it modulo 998 244 353.

Input

The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases.

The first line of the test case contains a single integer n (2 ≤ n ≤ 2 ⋅ 10^5) — number of jury members.

The second line contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 10^9) — the number of problems that the i-th member of the jury came up with.

The sum of n over all test cases does not exceed 2 ⋅ 10^5.

Output

For each test case, print one integer — the number of nice permutations, taken modulo 998 244 353.

Example

Input


4
2
1 2
3
5 5 5
4
1 3 3 7
6
3 4 2 1 3 3


Output


1
6
0
540

Note

Explanation of the first test case from the example:

There are two possible permutations, p = [1, 2] and p = [2, 1]. For p = [1, 2], the process is the following:

  1. the first jury member tells a task; 
  2. the second jury member tells a task; 
  3. the first jury member doesn't have any tasks left to tell, so they are skipped; 
  4. the second jury member tells a task. 



So, the second jury member has told two tasks in a row (in succession), so the permutation is not nice.

For p = [2, 1], the process is the following:

  1. the second jury member tells a task; 
  2. the first jury member tells a task; 
  3. the second jury member tells a task. 



So, this permutation is nice.
import java.util.*;
import java.io.*;

public class C {

    public void prayGod() throws IOException {
        int t = nextInt();
        while (t-- > 0) {
            int n = nextInt();
            int[] a = nextIntArray(n);

            long[] fact = new long[n + 1];
            long[] invFact = new long[n + 1];
            long[] inv = new long[n + 1];

            fact[0] = fact[1] = 1;
            inv[1] = invFact[0] = invFact[1] = 1;

            for (int i = 2; i <= n; i++) {
                fact[i] = (fact[i - 1] * i) % mod;
                inv[i] = mod - (mod / i) * inv[(int) mod % i] % mod;
                invFact[i] = invFact[i - 1] * inv[i] % mod;
            }

            if (n == 1) {
                out.println(1);
                continue;
            }

            sort(a);
            int minDelta = iinf, countMax = 0;

            for (int i = 0; i < n - 1; i++) {
                minDelta = Math.min(minDelta, a[n - 1] - a[i]);
            }

            for (int i = n - 1; i >= 0; i--) {
                if (a[i] == a[n - 1])
                    countMax++;
            }

            if (minDelta > 1) {
                out.println(0);
                continue;
            }

            if (countMax > 1) {
                out.println(fact[n]);
                continue;
            }

            int lowPool = 0;
            for (int i = 0; i < n; i++) {
                if (a[i] <= a[n - 1] - 2)
                    lowPool++;
            }

            long ret = fact[n];

            // out.println(lowPool);

            for (int i = lowPool; i >= 0; i--) {
                long right = i != 0 ? (fact[lowPool] * invFact[lowPool - i] % mod) : 1;
                long left = fact[n - i - 1];
                long total = (left * right) % mod;
                // out.printf("%d %d %d %d\n", i, left, right, total);
                ret = (ret - total + mod) % mod;
            }

            out.println(ret);

        }
    }

    public void printVerdict(boolean verdict) {
        if (verdict)
            out.println(VERDICT_YES);
        else
            out.println(VERDICT_NO);
    }

    static final String VERDICT_YES = "YES";
    static final String VERDICT_NO = "NO";
    static final boolean RUN_TIMING = true;
    static final boolean AUTOFLUSH = false;
    static final boolean FILE_INPUT = false;
    static final boolean FILE_OUTPUT = false;

    static int iinf = 0x3f3f3f3f;
    static long inf = (long) 1e18 + 10;
    static long mod = (long) 998244353;

    static char[] inputBuffer = new char[1 << 20];
    static PushbackReader in = new PushbackReader(new BufferedReader(new InputStreamReader(System.in)), 1 << 20);
    static PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)), AUTOFLUSH);

    // int data-type
    public int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

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

    public void sort(int[] a) {
        shuffle(a);
        Arrays.sort(a);
    }

    public static void printArray(int[] arr) {
        for (int i = 0; i < arr.length; i++)
            out.print(arr[i] + " ");
        out.println();
    }

    // long data-type
    public long nextLong() throws IOException {
        return Long.parseLong(next());
    }

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

    public static void printArray(long[] arr) {
        for (int i = 0; i < arr.length; i++)
            out.print(arr[i] + " ");
        out.println();
    }

    public void sort(long[] a) {
        shuffle(a);
        Arrays.sort(a);
    }

    // double data-type
    public double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    public double[] nextDoubleArray(int n) throws IOException {
        double[] arr = new double[n];
        for (int i = 0; i < n; i++)
            arr[i] = nextDouble();
        return arr;
    }

    public static void printArray(double[] arr) {
        for (int i = 0; i < arr.length; i++)
            out.print(arr[i] + " ");
        out.println();
    }

    // Generic type
    public <T> void sort(T[] a) {
        shuffle(a);
        Arrays.sort(a);
    }

    public static <T> void printArray(T[] arr) {
        for (int i = 0; i < arr.length; i++)
            out.print(arr[i] + " ");
        out.println();
    }

    public String next() throws IOException {
        int len = 0;
        int c;
        do {
            c = in.read();
        } while (Character.isWhitespace(c) && c != -1);
        if (c == -1) {
            throw new NoSuchElementException("Reached EOF");
        }
        do {
            inputBuffer[len] = (char) c;
            len++;
            c = in.read();
        } while (!Character.isWhitespace(c) && c != -1);
        while (c != '\n' && Character.isWhitespace(c) && c != -1) {
            c = in.read();
        }
        if (c != -1 && c != '\n') {
            in.unread(c);
        }
        return new String(inputBuffer, 0, len);
    }

    public String nextLine() throws IOException {
        int len = 0;
        int c;
        while ((c = in.read()) != '\n' && c != -1) {
            if (c == '\r') {
                continue;
            }
            inputBuffer[len] = (char) c;
            len++;
        }
        return new String(inputBuffer, 0, len);
    }

    public boolean hasNext() throws IOException {
        String line = nextLine();
        if (line.isEmpty()) {
            return false;
        }
        in.unread('\n');
        in.unread(line.toCharArray());
        return true;
    }

    public void shuffle(int[] arr) {
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int j = (int) (Math.random() * (n - i));
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

    public void shuffle(long[] arr) {
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int j = (int) (Math.random() * (n - i));
            long temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

    public void shuffle(Object[] arr) {
        int n = arr.length;
        for (int i = 0; i < n; i++) {
            int j = (int) (Math.random() * (n - i));
            Object temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

    public static void main(String[] args) throws IOException {
        if (FILE_INPUT)
            in = new PushbackReader(new BufferedReader(new FileReader(new File("output.txt"))), 1 << 20);
        if (FILE_OUTPUT)
            out = new PrintWriter(new FileWriter(new File("output.txt")));

        long time = 0;
        time -= System.nanoTime();
        new C().prayGod();
        time += System.nanoTime();

        if (RUN_TIMING)
            System.err.printf("%.3f ms%n", time / 1000000.0);

        out.flush();
        in.close();
    }
}