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) { // Return the number of games you can buy if (p > s) { return 0; } int k=p; int i = 0; while (s-k >= 0) { s-=k; ++i; k = k-d<=m?m:k-d; } return i; } 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(); } }