input_num = list(int(x) for x in input().split())
a = input_num[0]
b = input_num[1]
c = input_num[2]
d = input_num[3]

if min(input_num) < 1 or max(input_num) > 100:
    exit()

# 野菜をx個食べる (c + 1) * x = d
x = d // (c + 1)

if x > a:
    print(a)
elif c * x > b:
    print(b // c)
elif x > 0:
    print(x)
else:
    print(0)