#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    i=0
    while s>=0:
        s=s-p
        if p-d>=m:
            p=p-d
        else:
            p=m
        i=i+1
    if s==0:
        return i
    else:
        return i-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)