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 tempA = 0, tempB = 0, ans = 0;
        while(tempA + tempB <= d) {
            if(tempA + 1 <= a && tempB + c <= b) {
                tempA++;
                tempB += c;
                ans++;
            }
        }
        System.out.println(--ans);
    }
}