#!/bin/python3

import sys

def nextprice(p,m,d):
    if p < m:
        return m
    if p > m:
        return p
    return m

def howManyGames(p, d, m, s):
    num = 0
    n = nextprice(p,m,d)
    while s >= n:
        s-= n
        num += 1
        p = p-d
        n = nextprice(p,m,d)
    return num


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)