import Foundation

func + (lhs: NSDecimalNumber, rhs: NSDecimalNumber) -> NSDecimalNumber {
    return lhs.adding(rhs)//.decimalNumberByAdding(rhs)
}

func readInts() -> [Int]{
    readLine()!.split(separator: " ").map { Int($0)! }
}

func main(){
    let input = Int(readLine()!)!
    var deposit = 100
    
    for i in 1...Int(pow(10.0, 18.0)){
        deposit += deposit / 100
        if deposit >= input{
            print(i)
            return
        }
    }

}
main()
