import kotlin.math.min

fun main(args: Array<String>) {
    val (a, b, c, d) = readLine()!!.split(" ").map(String::toInt)
    val vegi0 = d / (c + 1)
    val vegi1 = min(vegi0, a)
    val meat = min(vegi1 * c, b)
    val vegi = meat / c
    println(vegi)
}