n = int(input())
A = list(map(int,input().split()))
count = [0]*4
for a in A:
    count[min(a,3)] += 1

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