import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = 0;
		n = sc.nextLong();

		long a = 100;
		int ans = 0;

		while (true) {
			ans++;
			long tmp = 0;
			tmp = (long) (a * 0.01);
			a += tmp;

			if(a >= n){
				System.out.println(ans);
				break;
			}

		}
	}
}
/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