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)}

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

    val p = Ps(halfway)
    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 <- comps
      h <- halfways
      if (c.score + h.score >= G)
    } yield c.count + h.count
  }

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