#!/bin/python3

import sys

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

            # Return the number of games you can buy

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)