import scala.io.StdIn

object Main extends App {
  val n = StdIn.readLong()
  var cnt = 0
  var cur = 100L
  while (cur < n) {
    cnt += 1
    cur += cur / 100
  }
  println(cnt)

  def readIntPair: (Int, Int) = {
    val Array(x, y) = StdIn.readLine().split(" ").map(_.toInt)
    (x, y)
  }
}