//b_1_percent
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = sc.nextLong();
		long yen_at_bank = 100;
		int year = 0;
		
		
		while(true) {
			year++;
			yen_at_bank = yen_at_bank + yen_at_bank / 100;
			if(yen_at_bank >= x) {
				System.out.println(year);
				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