#include<stdio.h>

int main(void){
  long long int x,sum;
  int i, year;
  sum = 100;
  year = 0;
  i = 1;
  scanf("%lld", &x);
  while(sum < x){
    if(sum >= 100*(i+1)){
      i = sum / 100;
    }
    sum += i;
    year += 1;
  }
  printf("%d", year);
  return 0;
}