#!/bin/python

import sys

def howManyGames(p, d, m, s):
    # Return the number of games you can buy
    num = 0
    price = p
    while(s>=price):
        num += 1
        s -= price
        if price>=(m+d):
            price -= d
        else:
            price = m
    return num       

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