object Main {

  def main(args: Array[String]): Unit = {
    import scala.io.StdIn._

//    val N = readLine().toInt
//    val Array(n, ) = readLine().split(" ").map(_.toInt)

    val Array(a, p) = readLine().split(" ").map(_.toInt)

    println((a * 3 + p) / 2)
  }
}