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 sum = 0;
    	int count = 0;
    	while (s >= sum){
    		if(p > m){
    			sum += p;
    			count++;
    			p = p - d;
    		}
    		else{
    			sum += m;
    			count++;
    		}
    			
    	}
		return count-1;
        // 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();
    }
}