data_s =input()

data_n = data_s.split(" ")

yasai = 0
yasai_f = int(data_n[0])
niku  = int(data_n[1])
nikubai = int(data_n[2])
saidai = int(data_n[3])

if saidai > nikubai:
	yasai = int(saidai/(nikubai+1))

if yasai > int(niku/nikubai):
	yasai = int(niku/nikubai)

if yasai > yasai_f:
	yasai = yasai_f


print(yasai)