#yuki1470
n=int(input())
a=sorted(map(int,input().split()))
x=a.count(1)
y=a.count(2)
z=n-x-y
res=y*(y-1)//2+y*z+z*(z-1)//2
res+=2*(x*(x-1)//2+x*z)
res+=3*x*y
print(res)