#!/bin/python

import sys

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

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