import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int howManyGames(int p, int d, int m, int s) {
        int ans=0;
        while(s>0)
        {
            s=s-p;
            ans++;
            if(p-d>m)
            p=p-d;
            else
                break;
        }
        p=m;
        while(s>0)
        {
            s=s-p;
            ans++;
        }
        if(s<0)
        return ans-1;
        return ans;
        // Return the number of games you can buy
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int p = in.nextInt();
        int d = in.nextInt();
        int m = in.nextInt();
        int s = in.nextInt();
        int answer = howManyGames(p, d, m, s);
        System.out.println(answer);
        in.close();
    }
}