N = int(input())
A = [int(i) for i in input().split()]

ONE = A.count(1)
TWO = A.count(2)
OTHER = len(A) -ONE -TWO

mex_1 = 1*(TWO*(TWO-1)/2 + OTHER*(OTHER-1)/2 +TWO*OTHER)
mex_2 = 2*(ONE*(ONE-1)/2 + ONE*OTHER) 
mex_3 = 3*(ONE*TWO)

sum = int(mex_1 + mex_2 + mex_3)

print(sum)