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

L = [0, 0, 0, 0]
for i in range(n):
    if A[i] <= 2:
        L[A[i]] += 1
    else:
        L[3] += 1

ans = 0
ans += L[1] * (L[1] - 1)
ans += L[2] * (L[2] - 1) // 2 + L[3] * (L[3] - 1) // 2
ans += 3 * L[1] * L[2]
ans += L[1] * L[3]
ans += L[2] * L[3]
print(ans)