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

count1 = 0
count2 = 0
count = 0
for i in A:
    if i == 1:count1 += 1
    elif i == 2:count2 += 2
    else:count += 1
S = count1 * (count1 - 1) + 3 * count1 * count2 + 2 * count1 * count + count2 * (count2 - 1) // 2 + count2 * count + count * (count-1)
print(S)