import sys
sys.setrecursionlimit(10 ** 6)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LC(): return list(input())
def IC(): return [int(c) for c in input()]
def MI(): return map(int, sys.stdin.readline().split())
INF = float('inf')
MOD = 10**9 + 7
def solve():
    N = II()
    A = LI()
    One = 0
    Two = 0
    Three = 0
    Other = 0
    for a in A:
        if(a==1):
            One+=1
        elif(a==2):
            Two+=1
        elif(a==3):
            Three+=1
        else:
            Other+=1
    import math
    def combinations_count(n, r):
        return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))
    Thrid = One*Two
    Second = combinations_count(One, 2) + One*Three
    First = (N*(N-1))//2 - Thrid -Second
    print(3*Thrid+2*Second + First)
    return
solve()