

import kotlin.math.*  
fun main(args : Array<String>){
    var k: Long = readLine()!!.toLong()
    
    var zandaka:Long = 100
    for (i in 1..k){
        zandaka = zandaka + (floor(zandaka.toDouble() * 0.01)).toLong()
        if (zandaka >= k){
            print(i.toString())
            break
        }
    }
}