using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static int howManyGames(int p, int d, int m, int s) 
    {
        int[] arrGames=new int[11];
    int priceAfterDiscount=0;
        int capability=0;
        for(int i=0;i<11;i++)
        {
            if(i==0)
                arrGames[i]=p;
            else
            {
              priceAfterDiscount= arrGames[i-1]-d;
                if(priceAfterDiscount>=m)
                    arrGames[i]=priceAfterDiscount;
                else
                    arrGames[i]=m;
            }              
                
        }
        
        for(int i=0;i<11;i++)
        {
            if(s>=arrGames[i])
            {                
                capability++;
               s=s- arrGames[i];
            }          
                
        }
        return capability;
        // Return the number of games you can buy
    }

    static void Main(String[] args) {
        string[] tokens_p = Console.ReadLine().Split(' ');
        int p = Convert.ToInt32(tokens_p[0]);
        int d = Convert.ToInt32(tokens_p[1]);
        int m = Convert.ToInt32(tokens_p[2]);
        int s = Convert.ToInt32(tokens_p[3]);
        int answer = howManyGames(p, d, m, s);
        Console.WriteLine(answer);
    }
}