#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(void){
	int x,i;
	double m,n;
	
	scanf("%lf",&m);
	
	//m = (double)x;
	
	
	
	n=100;i=0;
	
	while(1){
		if(n>=m)
			break;
		n*=1.01;
		//x=(int)n;
		//n=(double)x;
		n = floor(n);

		i++;
	}
	
	printf("%d\n",i);
	
	return 0;
}