#!/bin/python3

import sys

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

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)