import times, strutils, sequtils, math, algorithm, tables, sets, lists, intsets
import critbits, future, strformat, deques
template `max=`(x,y) = x = max(x,y)
template `min=`(x,y) = x = min(x,y)
template `mod=`(x,y) = x = x mod y
template scan2 = (scan(), scan())
template scan3 = (scan(), scan())
let read* = iterator: string {.closure.} =
    while true: (for s in stdin.readLine.split: yield s)
proc scan(): int = read().parseInt
proc scanf(): float = read().parseFloat
proc toInt(c:char): int =
    return int(c) - int('0')



proc solve():int=
  var
    n = scan()
    a = newseqwith(n,scan())
    one = a.count(1)
    two = a.count(2)
  result += (2*(one)*(one-1)).div(2)
  result += (2*(one)*(n-one))
  result+=(3*(one)*(two))
  result+=(1*(n-one)*(n-one-1)).div(2)

  

  
echo solve()