import sys
from sys import stdin
import math

N = int(stdin.readline())

A = list(map(int,stdin.readline().split()))

dic = {}
for i in A:
    if i not in dic:
        dic[i] = 0
    dic[i] += 1

x = math.factorial(N)

for i in dic:
    x //= math.factorial(dic[i])

print (x)