#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    total=0
    games=0
    while True:
        total+=p
        if total>s:
            break
        games+=1
        if (p-d)>=m:
            p=p-d
        else:
            p=m
    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)