#include <stdio.h>

int main (void)
{   
    double c_dou = 100;
    int c_int=100;
    double rate = 0.01;
    int year = -1,i;
    double X;

    scanf("%lf",&X);
    
    while(c_int <= X){
        c_dou = (double)c_int * 1.01;
        c_int = (int)c_dou;
        year++;
    }

    printf("%d\n",year);


    return 0;

}
