from collections import Counter

N, *A = map(int, open(0).read().split())

c = Counter(A)
ks = list(c)
result = 0
for i in range(len(ks) - 2):
    for j in range(i + 1, len(ks) - 1):
        for k in range(j + 1, len(ks)):
            result += c[i] * c[j] * c[k]
print(result)