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

public class Solution {
    
    static int dsum, cnt = 0;
    
    static void getdecsum(int p, int d, int m) {
        //System.out.println(p + " " + dsum);
        if(p<m)
            return;
        dsum -= p;
        if(dsum<0)
            return;
        cnt++;
        getdecsum(p - d, d, m);
        return;
    }

    static int howManyGames(int p, int d, int m, int s) {
        // Return the number of games you can buy
        dsum = s;
        getdecsum(p, d, m); 
        if(dsum<0)
            return cnt;
        //s -= dsum;
        //System.out.println(s + " " + cnt);
        cnt += dsum / m;
        return cnt;
    }

    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();
    }
}