#!/bin/python3

import sys

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