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.
def main():
    # mod=1000000007 
    # MOD THE ANSWER IF USING THIS
    mod=998244353
    max_n=200005
    nCr,fact =  make_nCr_mod(max_n,mod)
    
    tc=ri()
    for i in range(tc): 
        n=ri()
        a=ria()
        a=sorted(a)
        cnt=Counter(a)
        if a[-1]-a[-2]>=2:
            wi(0)
            continue
        if cnt[a[-1]]>=2:
            wi(fact[n])
        else:     
            k=cnt[a[-1]-1]
            # only thing that matters is subsequence which has a[-1] and k a[-1]-1
            # let a[-1] be p and a[-1]-1 be q
            # p can take any place in the subsequence except last position
            # length of subsequence is k+1 and p can take first k positions so atleast 1 q comes after p
            # ans = (total permutations) *(k/(k+1))
            wi((k*fact[n]*pow(k+1,mod-2,mod))%mod)

        
def rant():
    # RANT BEGINS-
    # 
    # Did you look at the constraints dummy? Read problem again carefully understand it correctly
    # Are base cases correct n=0,n=1,n=N or string is all 0 or all 1?
    # Take hints from time limits maybe n=1000 and m=100000 so if n^2 doesnt work n*m might work?? 
    # Upto 10^8 works under 2 sec
    # 
    # 1.Greedy? What matters what doesnt? Is my claim correct? 
    #   Does my implementation correctly implements the greedy i thought of? 
    #   Dictionary? keep a count of values if constraint on something is low(like only alphabets(26) count)? 
    # 
    # 2.DP? Think about state's ranges maybe one of the states have lesser possible values than it may look like? 
    #   Obviously think about order of evaluation?
    #   Max/Min Answer including ith element or Ways to Answer using first i elements?
    # 
    # 3.Binary Search?(Monotonic? any one directed order in which we have to perform something?)
    # 
    # 4.Graph?DSU?Edge property or Vertex property Read carefully? Bipartitenes Property??? Cycle Property??? 
    #   Hidden but dependency ordering of values(in 1d array or 2d Table/Array) is that of a graph???
    # 
    # 5.Number Theory?(GCD subtraction?)
    # 
    # 6.Bruteforce?(Redundant part of N which may not give answer?Constraints?)
    # 
    # 7.Range Queries?
    # 
    # 8.Any Equivalency?(We have A and B and have to do 
    #   something between them maybe difficult if there was A~C and C~B then A~B
    #   C could be max or min or some other thing)
    # 
    # 9.Reverse Engineering?(From Answer to quesn or last step to first step)
    #   (if i to i+1 formula not making sense make i to i-1 formula)
    #
    # 10.Constructive? Mod? Bruteforce for smaller case and analyze patterns?
    #
    # 11.String? Constructive Greedy example- 
    #   Bracket sequence make first part unknown open and second part unknown closed 
    #   Remember always only n//2 open and n//2 closed brackets are there
    #
    # 12.Combinatorics?--> (n to i-1 index ways) * (ith index ways) * Ways (for i-1 till 0 index)?
    #
    # 13.Look for patterns and dependency of the patterns(maybe only first row or column matters to construct other rows and columns)
    #   for smaller cases maybe make bruteforce solution and analyze the patterns
    # 
    # 14.Two-Pointer Solution or Optimization??
    # 
    # 15.Sets & Multisets faster and easier to copy in CPP
    # 
    # 16.Critical Observations-Observe carefully and think about effects of something happening given in quesn.
    #   For example-Maybe complex problem for all posns can be broken into easier sub problem for Even positions and Odd positions.
    #   because if observed carefully even and odd positions are getting affected independently then we can combine answer 
    #
    # RANT ENDS
    return "AAAAAAAAAAAAAAAAARRRGHHHHHHHHHHHHHHHHHHHHHHHH"
    
def position_dict(arr):
    posn={}
    for i in range(len(arr)):
        if arr[i] in posn:
            posn[arr[i]].append(i)
        else:
            posn[arr[i]]=[i]
    return posn

def SieveOfEratosthenes(limit):
    """Returns all primes not greater than limit."""
    isPrime = [True]*(limit+1)
    isPrime[0] = isPrime[1] = False
    primes = []
    for i in range(2, limit+1):
        if not isPrime[i]:continue
        primes += [i]
        for j in range(i*i, limit+1, i):
            isPrime[j] = False
    return primes

def memodict(f):
    """memoization decorator for a function taking a single argument"""
    class memodict(dict):
        def __missing__(self, key):
            ret = self[key] = f(key)
            return ret

    return memodict().__getitem__

def pollard_rho(n):
    """returns a random factor of n"""
    if n & 1 == 0:
        return 2
    if n % 3 == 0:
        return 3

    s = ((n - 1) & (1 - n)).bit_length() - 1
    d = n >> s
    for a in [2, 325, 9375, 28178, 450775, 9780504, 1795265022]:
        p = pow(a, d, n)
        if p == 1 or p == n - 1 or a % n == 0:
            continue
        for _ in range(s):
            prev = p
            p = (p * p) % n
            if p == 1:
                return math.gcd(prev - 1, n)
            if p == n - 1:
                break
        else:
            for i in range(2, n):
                x, y = i, (i * i + 1) % n
                f = math.gcd(abs(x - y), n)
                while f == 1:
                    x, y = (x * x + 1) % n, (y * y + 1) % n
                    y = (y * y + 1) % n
                    f = math.gcd(abs(x - y), n)
                if f != n:
                    return f
    return n

@memodict
def prime_factors(n):
    """returns a Counter of the prime factorization of n"""
    if n <= 1:
        return Counter()
    f = pollard_rho(n)
    return Counter([n]) if f == n else prime_factors(f) + prime_factors(n // f)

def distinct_factors(n):
    """returns a list of all distinct factors of n"""
    factors = [1]
    for p, exp in prime_factors(n).items():
        factors += [p**i * factor for factor in factors for i in range(1, exp + 1)]
    return factors

def all_factors(n):
    """returns a sorted list of all distinct factors of n"""
    small, large = [], []
    for i in range(1, int(n**0.5) + 1, 2 if n & 1 else 1):
        if not n % i:
            small.append(i)
            large.append(n // i)
    if small[-1] == large[-1]:
        large.pop()
    large.reverse()
    small.extend(large)
    return small

def make_nCr_mod(max_n=2 * 10**5, mod=10**9 + 7):
    max_n = min(max_n, mod - 1)

    fact, inv_fact = [0] * (max_n + 1), [0] * (max_n + 1)
    fact[0] = 1
    for i in range(max_n):
        fact[i + 1] = fact[i] * (i + 1) % mod

    inv_fact[-1] = pow(fact[-1], mod - 2, mod)
    for i in reversed(range(max_n)):
        inv_fact[i] = inv_fact[i + 1] * (i + 1) % mod

    def nCr_mod(n, r):
        res = 1
        while n or r:
            a, b = n % mod, r % mod
            if a < b:
                return 0
            res = res * fact[a] % mod * inv_fact[b] % mod * inv_fact[a - b] % mod
            n //= mod
            r //= mod
        return res

    return nCr_mod,fact

class DisjointSetUnion:
    def __init__(self, n):
        self.parent = [*range(n+1)]
        self.size = [1]*(n+1)
        self.min, self.max = [*range(n+1)], [*range(n+1)]
        self.count = n

    def get(self, a):
        """Returns the identifier (parent) of the set to which a belongs to!"""
        if self.parent[a] == a:
            return a
        x = a
        while a != self.parent[a]:
            a = self.parent[a]
        while x != self.parent[x]:
            self.parent[x], x = a, self.parent[x]
        return a

    def union(self, a, b):
        """Join two sets that contain a and b!"""
        a, b = self.get(a), self.get(b)
        if a != b:
            if self.size[a] > self.size[b]:
                a, b = b, a
            self.parent[a] = b
            self.size[b] += self.size[a]
            self.min[b] = min(self.min[a], self.min[b])
            self.max[b] = max(self.max[a], self.max[b])
            self.count -= 1

    def sz(self,a):
        return self.size[self.get(a)]
    
    def count_sets(self):
        """Returns the number of disjoint sets!"""
        return self.count
    
class SegmentTree:
    
    
    
    def __init__(self, data, default=0, func=max):
        """initialize the segment tree with data"""
        self._default = default
        self._func = func
        self._len = len(data)
        self._size = _size = 1 << (self._len - 1).bit_length()

        self.data = [default] * (2 * _size)
        self.data[_size:_size + self._len] = data
        for i in reversed(range(_size)):
            self.data[i] = func(self.data[i + i], self.data[i + i + 1])

    def __delitem__(self, idx):
        self[idx] = self._default

    def __getitem__(self, idx):
        return self.data[idx + self._size]

    def __setitem__(self, idx, value):
        idx += self._size
        self.data[idx] = value
        idx >>= 1
        while idx:
            self.data[idx] = self._func(self.data[2 * idx], self.data[2 * idx + 1])
            idx >>= 1

    def __len__(self):
        return self._len

    def query(self, start, stop):
        """func of data[start, stop]"""
        stop+=1
        start += self._size
        stop += self._size

        res_left = res_right = self._default
        while start < stop:
            if start & 1:
                res_left = self._func(res_left, self.data[start])
                start += 1
            if stop & 1:
                stop -= 1
                res_right = self._func(self.data[stop], res_right)
            start >>= 1
            stop >>= 1

        return self._func(res_left, res_right)

    def __repr__(self):
        return "SegmentTree({0})".format(self.data)

class SparseTable:
    def __init__(self, data, func=min):
        self.func = func
        self._data = _data = [list(data)]
        i, n = 1, len(_data[0])
        while 2 * i <= n:
            prev = _data[-1]
            _data.append([func(prev[j], prev[j + i]) for j in range(n - 2 * i + 1)])
            i <<= 1

    def query(self, start, stop):
        """func of data[start, stop)]"""
        depth = (stop + 1 - start).bit_length() - 1
        return self.func(self._data[depth][start], self._data[depth][stop + 1 - (1 << depth)])

    def __getitem__(self, idx):
        return self._data[0][idx]
              
class SortedList:
    def __init__(self, iterable=[], _load=200):
        """Initialize sorted list instance."""
        values = sorted(iterable)
        self._len = _len = len(values)
        self._load = _load
        self._lists = _lists = [values[i:i + _load] for i in range(0, _len, _load)]
        self._list_lens = [len(_list) for _list in _lists]
        self._mins = [_list[0] for _list in _lists]
        self._fen_tree = []
        self._rebuild = True
 
    def _fen_build(self):
        """Build a fenwick tree instance."""
        self._fen_tree[:] = self._list_lens
        _fen_tree = self._fen_tree
        for i in range(len(_fen_tree)):
            if i | i + 1 < len(_fen_tree):
                _fen_tree[i | i + 1] += _fen_tree[i]
        self._rebuild = False
 
    def _fen_update(self, index, value):
        """Update `fen_tree[index] += value`."""
        if not self._rebuild:
            _fen_tree = self._fen_tree
            while index < len(_fen_tree):
                _fen_tree[index] += value
                index |= index + 1
 
    def _fen_query(self, end):
        """Return `sum(_fen_tree[:end])`."""
        if self._rebuild:
            self._fen_build()
 
        _fen_tree = self._fen_tree
        x = 0
        while end:
            x += _fen_tree[end - 1]
            end &= end - 1
        return x
 
    def _fen_findkth(self, k):
        """Return a pair of (the largest `idx` such that `sum(_fen_tree[:idx]) <= k`, `k - sum(_fen_tree[:idx])`)."""
        _list_lens = self._list_lens
        if k < _list_lens[0]:
            return 0, k
        if k >= self._len - _list_lens[-1]:
            return len(_list_lens) - 1, k + _list_lens[-1] - self._len
        if self._rebuild:
            self._fen_build()
 
        _fen_tree = self._fen_tree
        idx = -1
        for d in reversed(range(len(_fen_tree).bit_length())):
            right_idx = idx + (1 << d)
            if right_idx < len(_fen_tree) and k >= _fen_tree[right_idx]:
                idx = right_idx
                k -= _fen_tree[idx]
        return idx + 1, k
 
    def _delete(self, pos, idx):
        """Delete value at the given `(pos, idx)`."""
        _lists = self._lists
        _mins = self._mins
        _list_lens = self._list_lens
 
        self._len -= 1
        self._fen_update(pos, -1)
        del _lists[pos][idx]
        _list_lens[pos] -= 1
 
        if _list_lens[pos]:
            _mins[pos] = _lists[pos][0]
        else:
            del _lists[pos]
            del _list_lens[pos]
            del _mins[pos]
            self._rebuild = True
 
    def _loc_left(self, value):
        """Return an index pair that corresponds to the first position of `value` in the sorted list."""
        if not self._len:
            return 0, 0
 
        _lists = self._lists
        _mins = self._mins
 
        lo, pos = -1, len(_lists) - 1
        while lo + 1 < pos:
            mi = (lo + pos) >> 1
            if value <= _mins[mi]:
                pos = mi
            else:
                lo = mi
 
        if pos and value <= _lists[pos - 1][-1]:
            pos -= 1
 
        _list = _lists[pos]
        lo, idx = -1, len(_list)
        while lo + 1 < idx:
            mi = (lo + idx) >> 1
            if value <= _list[mi]:
                idx = mi
            else:
                lo = mi
 
        return pos, idx
 
    def _loc_right(self, value):
        """Return an index pair that corresponds to the last position of `value` in the sorted list."""
        if not self._len:
            return 0, 0
 
        _lists = self._lists
        _mins = self._mins
 
        pos, hi = 0, len(_lists)
        while pos + 1 < hi:
            mi = (pos + hi) >> 1
            if value < _mins[mi]:
                hi = mi
            else:
                pos = mi
 
        _list = _lists[pos]
        lo, idx = -1, len(_list)
        while lo + 1 < idx:
            mi = (lo + idx) >> 1
            if value < _list[mi]:
                idx = mi
            else:
                lo = mi
 
        return pos, idx
 
    def add(self, value):
        """Add `value` to sorted list."""
        _load = self._load
        _lists = self._lists
        _mins = self._mins
        _list_lens = self._list_lens
 
        self._len += 1
        if _lists:
            pos, idx = self._loc_right(value)
            self._fen_update(pos, 1)
            _list = _lists[pos]
            _list.insert(idx, value)
            _list_lens[pos] += 1
            _mins[pos] = _list[0]
            if _load + _load < len(_list):
                _lists.insert(pos + 1, _list[_load:])
                _list_lens.insert(pos + 1, len(_list) - _load)
                _mins.insert(pos + 1, _list[_load])
                _list_lens[pos] = _load
                del _list[_load:]
                self._rebuild = True
        else:
            _lists.append([value])
            _mins.append(value)
            _list_lens.append(1)
            self._rebuild = True
 
    def discard(self, value):
        """Remove `value` from sorted list if it is a member."""
        _lists = self._lists
        if _lists:
            pos, idx = self._loc_right(value)
            if idx and _lists[pos][idx - 1] == value:
                self._delete(pos, idx - 1)
 
    def remove(self, value):
        """Remove `value` from sorted list; `value` must be a member."""
        _len = self._len
        self.discard(value)
        if _len == self._len:
            raise ValueError('{0!r} not in list'.format(value))
 
    def pop(self, index=-1):
        """Remove and return value at `index` in sorted list."""
        pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
        value = self._lists[pos][idx]
        self._delete(pos, idx)
        return value
 
    def bisect_left(self, value):
        """Return the first index to insert `value` in the sorted list."""
        pos, idx = self._loc_left(value)
        return self._fen_query(pos) + idx
 
    def bisect_right(self, value):
        """Return the last index to insert `value` in the sorted list."""
        pos, idx = self._loc_right(value)
        return self._fen_query(pos) + idx
 
    def count(self, value):
        """Return number of occurrences of `value` in the sorted list."""
        return self.bisect_right(value) - self.bisect_left(value)
 
    def __len__(self):
        """Return the size of the sorted list."""
        return self._len
 
    def __getitem__(self, index):
        """Lookup value at `index` in sorted list."""
        pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
        return self._lists[pos][idx]
 
    def __delitem__(self, index):
        """Remove value at `index` from sorted list."""
        pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
        self._delete(pos, idx)
 
    def __contains__(self, value):
        """Return true if `value` is an element of the sorted list."""
        _lists = self._lists
        if _lists:
            pos, idx = self._loc_left(value)
            return idx < len(_lists[pos]) and _lists[pos][idx] == value
        return False
 
    def __iter__(self):
        """Return an iterator over the sorted list."""
        return (value for _list in self._lists for value in _list)
 
    def __reversed__(self):
        """Return a reverse iterator over the sorted list."""
        return (value for _list in reversed(self._lists) for value in reversed(_list))
 
    def __repr__(self):
        """Return string representation of sorted list."""
        return 'SortedList({0})'.format(list(self))

import sys, os, io ,copy
def rs(): return sys.stdin.readline().rstrip()
def ri(): return int(sys.stdin.readline())
def ria(): return list(map(int, sys.stdin.readline().split()))
def ws(s): sys.stdout.write(s + '\n')
def wi(n): sys.stdout.write(str(n) + '\n')
def wia(a): sys.stdout.write(' '.join([str(x) for x in a]) + '\n')
import math,datetime,functools,itertools,operator,bisect,fractions,statistics
from math import log2
from bisect import bisect_left,bisect_right
from collections import deque,defaultdict,OrderedDict,Counter
from fractions import Fraction
from decimal import Decimal
from sys import stdout
from heapq import heappush, heappop, heapify ,_heapify_max,_heappop_max,nsmallest,nlargest
# sys.setrecursionlimit(111111) 
INF=999999999999999999999999
alphabets="abcdefghijklmnopqrstuvwxyz"

class FastReader(io.IOBase):
    newlines = 0

    def __init__(self, fd, chunk_size=1024 * 8):
        self._fd = fd
        self._chunk_size = chunk_size
        self.buffer = io.BytesIO()

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, self._chunk_size))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self, size=-1):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, self._chunk_size if size == -1 else size))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

class FastWriter(io.IOBase):

    def __init__(self, fd):
        self._fd = fd
        self.buffer = io.BytesIO()
        self.write = self.buffer.write

    def flush(self):
        os.write(self._fd, self.buffer.getvalue())
        self.buffer.truncate(0), self.buffer.seek(0)

class FastStdin(io.IOBase):
    def __init__(self, fd=0):
        self.buffer = FastReader(fd)
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")

class FastStdout(io.IOBase):
    def __init__(self, fd=1):
        self.buffer = FastWriter(fd)
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.flush = self.buffer.flush

if __name__ == '__main__':
    sys.stdin = FastStdin()
    sys.stdout = FastStdout()
    starttime=datetime.datetime.now()
    if(os.path.exists('input.txt')):
        sys.stdin = open("input.txt","r")
        sys.stdout = open("output.txt","w")
    main()
    endtime=datetime.datetime.now()
    time=(endtime-starttime).total_seconds()*1000
    if(os.path.exists('input.txt')):
        print("Time:",time,"ms")  
    