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

int main (void){
  
  long X;
  long deposit = 100;
  int years = 0;
  scanf("%ld",&X);
  long rishi = 0;
  
  while(deposit<X){
    years ++;
    deposit += deposit / 100;
  }
  printf("%d",years);
  
  return 0;
}