n = int(input())

a = list(map(int,input().split()))
a.sort()
cnt = 1
b = []
now = a[0]
for i in range(1, n):
    if now != a[i]:
        b.append(cnt)
        now = a[i]
        cnt = 1
    else:
        cnt += 1
b.append(cnt)

ans = 1

for i in range(1, n + 1):
    ans *= i

for v in b:
    for i in range(1, v + 1):
        ans //= i
print(ans)