object Main extends App {
  import scala.io.StdIn.{ readInt, readLine }
  val n = readInt()
  def loop(x: Int): Unit = {
    if (x == 0) {
      ()
    } else {
      val as = readLine().toList.map(_.toInt - 48)
      val bs = readLine().toList.map(_.toInt - 48)

      val al = as.length
      if (80 < al) {
        println("overflow")
        loop(x - 1)
        return
      }
      val bl = bs.length
      if (80 < bl) {
        println("overflow")
        loop(x - 1)
        return
      }

      val padding = if (al < bl) bl - al else al - bl
      val ts =
        if (al < bl) as.reverse ++ List.fill[Int](padding)(0) zip bs.reverse
        else         as.reverse zip bs.reverse ++ List.fill[Int](padding)(0)

      var f = false
      val rs = ts.map { t =>
        val tmp = if (f) t._1 + t._2 + 1 else t._1 + t._2
        f = if (tmp < 10) false else true
        tmp % 10
      }

      val ans = if (f) 1 :: rs.reverse else rs.reverse
      if (80 < ans.mkString.length) println("overflow") else println(ans.mkString)

      loop(x - 1)
    }
  }
  loop(n.toInt)
}