def RunLengthEncoding(S):
    res = []
    N = len(S)
    i = 0
    while i < N:
        cnt = 1
        while i < N - 1 and S[i] == S[i + 1]:
            cnt += 1
            i += 1
        res.append(cnt)
        i += 1
    return res


N = int(input())
A = list(map(int, input().split()))
A.sort()

RLE = RunLengthEncoding(A)
fact = [1] * (N + 1)
for i in range(1, N+1):
    fact[i] = fact[i-1] * i

ok = 1
for i in RLE:
    ok *= fact[i]

print(fact[N] // ok)