#!/bin/python

import sys

def howManyGames(p, D, m, s):
	# Return the number of games you can buy
	current = 0
	no = 0
	d = 0
	while current <= s:
		if p -d >= m:
			current = current + p - d
			d = d + D
		else:
			current = current + m
		# print current
		if current <= s:
			no = no + 1
	# print no
	return no

if __name__ == "__main__":
    p, d, m, s = raw_input().strip().split(' ')
    p, d, m, s = [int(p), int(d), int(m), int(s)]
    answer = howManyGames(p, d, m, s)
    print answer