from collections import Counter
n = int(input())
A = sorted(list(map(int,input().split())))
C = Counter(A)
ans = 1
base = 1
done = {}
num = 0
for a in A[::-1]:
    if a in done:
        continue
    count = C[a]
    for j in range(count,0,-1):
        ans *= n-num
        base *= j
        num += 1
    done[a] = 1
print(ans//base)