N = int(input())
A = list(map(int,input().split()))
a = 0
b = 0
c = 0
for i in range(N):
    if A[i] == 1:
        a += 1
    elif A[i] == 2:
        b += 1
    else:
        c += 1
sum = 0
sum += 2 * a * (a-1) // 2
sum += 3 * a * b
sum += 1 * b * c
sum += 2 * a * c
sum += b * (b-1) //2
sum += c * (c-1) // 2
print(sum)