import scala.io.StdIn.readLine
import scala.io.StdIn.readInt
import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)
  val x = sc.nextDouble()
  var m = 100.0
  var y = 0
  do{
    y += 1
    m *= 1.01
    m =  m.floor
  }while(m < x)
  println(y)
}