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 totalMoney = s;
        int numGames = 1;
        totalMoney = totalMoney-p;
        int currCost = p;

        while(currCost > m && totalMoney >= currCost){
            currCost = currCost-d;
            totalMoney = totalMoney - currCost;
            numGames++;
            //System.out.println(currCost);
        }
        totalMoney=totalMoney-currCost;
        while(totalMoney>=currCost){
            //System.out.println(totalMoney);
            totalMoney = totalMoney-currCost;
            numGames++;
            //System.out.println(currCost);
        }
        return numGames;
        
    }

    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();
    }
}