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

#define rep(i,a,b) for(int i = a; i <= b;i++)


int main(void){
  long long int x;
  scanf("%lld",&x);
  long long int year = 0;
  long long int money = 100;
  while(money < x){
    year ++;
    money += money/100;
  }
  printf("%lld",year);

  return 0;
}
