# coding: utf-8
a, b, c, d = map(int, input().split())
lim = [101, 101, 101]
lim[0] = d // (1 + c)
if a < lim[0]:
    lim[1] = a
if lim[0] * c > b:
    lim[2] = b // c
print(min(lim))