import sequtils,math
template times*(n:int,body) = (for _ in 0..<n: body)
template `max=`*(x,y) = x = max(x,y)
template `min=`*(x,y) = x = min(x,y)

proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  result = 0
  var minus = false
  while true:
    var k = getchar_unlocked()
    if k == '-' : minus = true
    elif k < '0' or k > '9': break
    else: result = 10 * result + k.ord - '0'.ord
  if minus: result *= -1
type BinaryIndexedTree[T] = ref object
  data: seq[T] # 引数以下の部分和(Fenwick Tree)
proc initBinaryIndexedTree[T](n:int):BinaryIndexedTree[T] =
  new(result)
  result.data = newSeq[T](n)
proc len[T](self:BinaryIndexedTree[T]): int = self.data.len()
proc update[T](self:var BinaryIndexedTree[T],i:int,val:T) =
  var i = i
  while i < self.len():
    self.data[i] += val
    i = i or (i + 1)
proc `[]`[T](self:BinaryIndexedTree[T],i:int): T =
  var i = i
  while i >= 0:
    result += self.data[i]
    i = (i and (i + 1)) - 1
proc `$`[T](self:BinaryIndexedTree[T]): string =
  result = "["
  for i in 0..<self.len.min(100): result &= $(self[i]) & ", "
  return result[0..result.len()-2] & (if self.len > 100 : " ...]" else: "]")

var last = 0
let n = scan()
let k = scan()
var cargo =  initBinaryIndexedTree[int](100_0001)
n.times:
  let w = scan()
  if w > 0:
    if last - cargo[w-1] >= k: continue # W以上の荷物がK個以上
    cargo.update w, 1
    last += 1
  else:
    if cargo[-w-1] == cargo[-w] : continue # 荷物が無い
    cargo.update -w,-1
    last -= 1
echo last