object Main{
  def main(args: Array[String]) = {
    val input=io.Source.stdin.getLines().mkString("\n")
    println(solve(input).trim())
  }

  def solve(input:String):String={
    val Array(a,b,x,y) = input.split(" ").map(_.toInt)
    (Array(x/a.toDouble, y/b.toDouble).min*(a+b)).toString
  }
}