import algorithm, hashes, macros, math, sequtils, sets, strutils, tables, times, unicode

macro unpack*(rhs: seq, cnt: static[int]): auto =
  let t = genSym(); result = quote do:(let `t` = `rhs`;())
  if NimMinor <= 17:
    for i in 0..<cnt: result[0][1].add(quote do:`t`[`i`])
  else:
    for i in 0..<cnt: result[1].add(quote do:`t`[`i`])

template input*(typ: typedesc, cnt: Natural = 0): untyped =
  let line = stdin.readLine.split(" ")
  when cnt == 0:
    when typ is int:    @[0]   & line.map(parseInt)
    elif typ is float:  @[0.0] & line.map(parseFloat)
    elif typ is string: @["#"] & line
  else:
    when typ is int:    line.map(parseInt).unpack(cnt)
    elif typ is float:  line.map(parseFloat).unpack(cnt)
    elif typ is string: "#" & line.unpack(cnt)

# -------------------------------------------------- #

var (A, B, C, D) = input(int, 4)
var res = 0
var cnt = 0
while true:
  if A >= 1 and B >= C and cnt + 1 + C <= D:
    A -= 1
    B -= C
    cnt += 1 + C
    res.inc()
  else:
    break
echo res