import sequtils
import times
template stopwatch(body) = (let t1 = cpuTime();body;echo "TIME:",(cpuTime() - t1) * 1000,"ms")
template stopwatch(body) = body
proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  while true:
    let k = getchar_unlocked()
    if k < '0': return
    result = 10 * result + k.ord - '0'.ord

let n = scan()
var data: array[200010,int32]
var E : array[200010,seq[int32]]
proc update(i:int,val:int32) =
  var i = i
  while i < n:
    data[i] += val
    i = i or (i + 1)
proc get*(i:int): int32 =
  var i = i
  while i >= 0:
    result += data[i]
    i = (i and (i + 1)) - 1

stopwatch:
  for i in 1.int32..<n.int32: E[scan()] &= i
  proc solve(x:int): int =
    result += get(x)
    update(x, 1)
    for e in E[x]: result += solve(e)
    update(x, -1)
  stopwatch:
    echo solve(0)