# /usr/bin/python
# -*- coding: utf-8 -*-
#
import sys


def solve(A,B,C,D):
  ans = 0
  while(1):
    if ans > A or C*ans > B:
      return max(ans-1, 0)
    elif (1+C)*ans > D:
      return max(ans-1, 0)
    else:
      ans += 1


a,b,c,d = map(int, input().split())
print(solve(a,b,c,d))