#include<stdio.h>

int main(void){

	long long int X, m, ans;
	m = 100;
	ans = 0;

	scanf("%lld", &X);

	for(; ;){

		ans++;
		m = m + m / 100;

		if(m >= X){
			break;
		}

	}

	printf("%lld", ans);

	return 0;
}