import strutils
 
let read* = iterator: string =
  while true: (for s in stdin.readLine.split: yield s)
 
template input*(T: static[typedesc]): untyped = 
  when T is int: read().parseInt
  elif T is float: read().parseFloat
  elif T is string: read()
  elif T is char: read()[0]

let A, B, C, D = input(int)
for R in countdown(A, 0):
  if R * C <= B and R + R * C <= D:
    echo R; quit(0)