import math

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

group_counts = []
current = A[0]
count = 1

for num in A[1:]:
    if num == current:
        count += 1
    else:
        group_counts.append(count)
        current = num
        count = 1
group_counts.append(count)  # Add the last group

product = 1
for c in group_counts:
    product *= math.factorial(c)

n_fact = math.factorial(n)
ans = n_fact // product

print(ans)