object Main {
  def main(args: Array[String]): Unit = {
    val sc = new java.util.Scanner(System.in)
    val fredgeCount: Int = sc.nextInt()
    val microwaveCount: Int = sc.nextInt()
    val ticketCount: Int = sc.nextInt()

    val fredges: Array[Int] = Array.fill(fredgeCount)(sc.nextInt())
    val microwaves: Array[Int] = Array.fill(microwaveCount)(sc.nextInt())
    val tickets: Array[(Int, Int, Int)] =
      Array.fill(ticketCount)((sc.nextInt(), sc.nextInt(), sc.nextInt()))

    val ticketMin =
      tickets.map { ticket =>
        val (fredge, microwave, discount) = ticket
        val fredgePrice = fredges(fredge - 1)
        val microwavePrice = microwaves(microwave - 1)
        fredgePrice + microwavePrice - discount
      }.min

    val fredgeMin = fredges.min
    val microwaveMin = microwaves.min
    val nonTicketMin = fredgeMin + microwaveMin

    val ans = Math.min(ticketMin, nonTicketMin)

    println(ans)
  }
}
