#!/usr/bin/env PyPy3

from collections import Counter, defaultdict, deque
import itertools
import re
import math
from functools import reduce
import operator
import bisect
import heapq
import functools
mod=10**9+7

import sys
input=sys.stdin.readline
#nCrをmodで割ったあまりを求める
def cmb(n, r):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    res = 1
    for i in range(1,n+1):
        res *= i
    for i in range(1,r+1):
        res //= i
    for i in range(1,n-r+1):
        res //= i
    return res
n=int(input())
a=list(map(int,input().split()))
a.sort()
d = defaultdict(int)
for aa in a:
    d[aa] += 1
used = [0] * (n+1)
c = 1
rem = n
for aa in a:
    if used[aa]:
        continue
    used[aa] = 1
    c *= cmb(rem,d[aa])
    rem -= d[aa]

print(c)