#include<stdio.h>

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