def main():

  count_list = []
  str_list = input().split()

  count_list = [int(s) for s in str_list]

  yasai = count_list[0]
  niku = count_list[1]
  per_yasai = count_list[2]
  mannpuku = count_list[3]

  ate_yasai = 0
  eat_food = yasai // yasai + per_yasai

  while yasai > 0 and niku > 0 and mannpuku >= eat_food:
    yasai -= 1
    niku -= per_yasai
    mannpuku = mannpuku - eat_food
    ate_yasai += 1
  print(ate_yasai)

if __name__ == "__main__":
  main()