#!/bin/python

import sys

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

if __name__ == "__main__":
    p, d, m, s = raw_input().strip().split(' ')
    p, d, m, s = [int(p), int(d), int(m), int(s)]
    answer = howManyGames(p, d, m, s)
    print answer