#include <stdio.h>
#include <math.h>

int main(void){

  double x;
  scanf("%lf", &x);
  double takahashi = 100;
  for (long i = 1; ; i++) {
    takahashi *= 1.01;
    takahashi = floor(takahashi);
    if (takahashi >= x) {
      printf("%ld\n", i);
      break;
    }
  }

  return 0;
}