#!/bin/python3

import sys

def howManyGames(p, d, m, s):
	sum=0
	n=0
	count=0
	cost=0
	while(True):
		if(sum<=s):
			cost=p-n*d
			if cost>=m:
				sum=sum+cost
				n=n+1
				count=count+1
			elif cost<m:
				sum=sum+m
				count=count+1
		elif sum>s:
			return count-1


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