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

cnt1 = 0
cnt2 = 0

for a in A:
    if a == 1:
        cnt1 += 1
    elif a == 2:
        cnt2 += 1

res = (cnt1 - 1) * cnt1 // 2 * 2 + cnt1 * cnt2 * 3 + N * (N - 1) // 2 - cnt1 * cnt2 - (cnt1 - 1) * cnt1 // 2

print(res)