object Main extends App {
  case class Problem(n: Int, ratio: Long, bonus: Long) {
    val completeScore = n * ratio + bonus
  }
  case class Result(score: Long, count: Int)

  val in = new java.util.Scanner(System.in)
  val D = in.nextInt
  val G = in.nextLong / 100

  val Ps = Array.tabulate(D){i => Problem(in.nextInt, i + 1, in.nextLong / 100)}
  val comps: IndexedSeq[Result] = (0 until (1 << D)).map {mask =>
    (0 to D).foldLeft(Result(0L, 0)) {case (r, i) =>
      if (((1 << i) & mask) == 0) r else Result(r.score + Ps(i).completeScore, r.count + Ps(i).n)
    }
  }

  def getAll(i: Int): Seq[Int] = {
    val targetComps: Seq[Result] = (0 until (1 << D)).flatMap {mask =>
      if (((1 << i) & mask) != 0) None else Some(comps(mask))
    }

    val p = Ps(i)
    val halfways: Seq[Result] = (0 to p.n).map {n =>
      if (n == p.n) Result(p.completeScore, n) else Result(n * p.ratio, n)
    }

    for {
      c <- targetComps
      h <- halfways
      if (c.score + h.score >= G)
    } yield c.count + h.count
  }

  println((0 until D).flatMap(getAll).min)
}