import sys,math,itertools
from collections import Counter,deque,defaultdict
from bisect import bisect_left,bisect_right 
from heapq import heappop,heappush,heapify
mod = 10**9+7
INF = float('inf')
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpl_1(): return list(map(lambda x:int(x)-1, sys.stdin.readline().split()))
def inps(): return sys.stdin.readline()
def inpsl(x): tmp = inps(); return list(tmp[:x])
def err(x): print(x); exit()

n = inp()
a = inpl()
cnt = [0,0,0]
for x in a:
    if x >= 3: x = 3
    cnt[x-1] += 1
res = 0
res += 3*cnt[1]*cnt[0]
res += 2*cnt[0]*cnt[2]
res += 1*cnt[1]*cnt[2]
res += cnt[0]*(cnt[0]-1)
res += (cnt[1]*(cnt[1]-1) + cnt[2]*(cnt[2]-1))//2
print(res)