#!/bin/python3

import sys

def howManyGames(price, dec, minimum, wallet):
    games = 0
    while wallet >= 0 :
        wallet = wallet - price
        games = games + 1 if wallet >= 0 else games
        price = price - dec if price - dec > minimum else minimum
    return games
            

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)