import java.util.Scanner

object Main {
  def main(args: Array[String]): Unit = {
    //nextLineとnextを同時に使ったら死ぬ
    val sc = new Scanner(System.in)

    val x = BigInt(sc.nextBigInteger())

    var count = 0
    var now = 100L
    while (now < x) {
      count += 1
      now = now + now / 100L
    }

    println(count)
  }

  @scala.annotation.tailrec
  def gcd(a: Int, b: Int): Int = {
    if (b == 0) a else gcd(b, a % b)
  }
  def debug(args: Any*): Unit = {
    Console.err.println(args.mkString(" "))
  }
}
