object Main extends App {
  val n = readInt
  (1 to n)
    .map(_ => (readLine, readLine))
    .map {
      case (str1, str2) =>
        if (str1.length > 80 || str2.length > 80) "overflow"
        else {
          val (bi1, bi2) = (BigInt(str1), BigInt(str2))
          val ans = bi1 + bi2
          if (ans.toString.length > 80) "overflow"
          else ans.toString
        }
    }
    .foreach(println)
}

