import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);
		long x = sca.nextLong();
		long money = 100;
		int year = 1;
		boolean flag = false;

		do {
			money = money + (money/100);
			if(money >= x) {
				System.out.println(year);
				flag = true;
			}
			year++;
		} while(!flag);

		// 後始末
		sca.close();
	}
}
/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