import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		long X = Long.parseLong(scan.nextLine());
		long P = 100;
		int cnt = 0;

		for (int i = 0; i < 3800; i++){
			if (X > P){
				P += P / 100;
				cnt++;
			}else {
				System.out.println(cnt);
				return;
			}
		}
	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz