#!/bin/python3

import sys

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

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)