line = input().split(" ")
vegi = int(line[0])
meat = int(line[1])
meatCons = int(line[2])
vegicons = 1
total = int(line[3])
cnt = 0

while True:
    vegi -= 1
    meat -= meatCons
    total -= (vegicons + meatCons)
    if (vegi < 0 or meat < 0):
        break
    if (total < 0):
        break
    cnt += 1

print(cnt)