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

int main(void) {
  long long int X;
  long long int year = 0;

  long long int money = 100;

  scanf("%lld",&X);

  while(money < X){
    money += (money / 100);
    year++;
  }

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

  return 0;
}
