#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    # Return the number of games you can buy
    answer=0
    sum=0
    while sum<=s:
        if p<=m:
            sum+=m
            answer+=1
        else:
            sum+=p
            p=p-d
            answer+=1
    return(answer-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)