import java.util.Scanner;

public class Main {
	static final int a = 100;
	static final double r = 1.01;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long x = Long.parseLong(sc.next());
		System.out.println(solve(x));
	}

	static public int solve(long x) {
		int year = 0;
		for (long i = a;; i = (long) (i * r), year++) {
			if (i >= x)
				return year;
		}
	}

}

/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