import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());
        int ans = Math.min(d / (c + 1), Math.min(a, b / c));
        System.out.println(ans);
    }
}