#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    # Return the number of games you can buy
    priceList = []
    priceList.append(p)
    if(p>s):
        return(0)
    if(p==s):
        return(1)
    sum=p
    t=p
    while(True):
        t=t-d
        item=0
        if(t<=m):
            item=m
        else:
            item=t
        sum = sum + item
        if(sum<=s):
            priceList.append(item)
        else:
            break
    return(len(priceList))
            
            
        

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)