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

mex2 = (cnt1 - 1) * cnt1 // 2 + cnt1 * (N - cnt1 - cnt2)
mex3 = cnt1 * cnt2
mex1 = N * (N - 1) // 2 - mex2 - mex3

res = mex1 + 2 * mex2 + 3 * mex3

print(res)