/* 165b.c */
#include <stdio.h>
#include <math.h>
double floor(double);

int main(void){
    double x=0;
    double risi=0;
    double yokin=100;
    scanf("%lf",&x);
    for(int i=1;i<yokin;i++){
        risi=floor((double)yokin*1/100);
        yokin=floor((double)yokin+(double)risi); 
        if(x<=yokin){
            printf("%d",i);
            return 0;
        }
        //printf("%lf\n",yokin);
    }
    printf("error");
}