import java.util.*;

class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();
		int d = sc.nextInt();
		int i;
		for(i = 1; i <= a && i*c <= b && i*c+i <= d; i++){
		}
		System.out.print(--i);
	}
}