package test.demo;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Yukicoder804 {

	public static void main(String[] args) throws IOException {
		// TODO 自動生成されたメソッド・スタブ
		String[] str=input();
		int A=Integer.parseInt(str[0]);
		int B=Integer.parseInt(str[1]);
		int C=Integer.parseInt(str[2]);
		int D=Integer.parseInt(str[3]);
		int eatA=0;
		

			for(int j=1;j<=A&&j*3<=B;j++) {
				if((C+1)*j>D) {
					break;
				}
				eatA=j;
			}
		
		System.out.println(eatA);

	}
	public static  String[] input() throws IOException {
		BufferedReader br =new BufferedReader(new InputStreamReader(System.in));
		
		String str=br.readLine();
		String[]str2=str.split(" ");
		
		return str2;
	}
}