import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################


n = ni()
from collections import defaultdict
A = defaultdict(int)
def fact(x):
    r = 1
    for i in range(x):
        r *= i+1
    return r
for i in na():
    A[i] += 1
ans = 1
for i in A:
    i = A[i]
    ans *= fact(n)//fact(n-i)//fact(i)
    n -= i
print(ans)