package main

import "fmt"

func main() {
	var a, b, c, d int
	fmt.Scan(&a, &b, &c, &d)
	ans := 0
	for v := 0; v <= a; v++ {
		if v*c <= b && v+v*c <= d {
			if v > ans {
				ans = v
			}
		}
	}
	fmt.Println(ans)
}