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()
    m = newseqwith(n,scan())
    bittree = newseqwith(n+1,0)


  proc add(a,w:int)=
    var x = a
    while x<=n:
      bittree[x]+=w
      x += x and (-x)

  proc sum(a:int):int=
    var x = a
    while x>0:
      result+=bittree[x]
      x -= x and (-x)


  for i in countdown(n-1,0):
    result+=sum(m[i])
    add(m[i],1)
  
echo solve()