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

int main(){

  long long cnt = 0;
  long long x;
  long long m = 100;

  scanf("%lld", &x);

  while(1){
    cnt++;
    m = m + m*0.01;

    if(m >= x) break;
  }

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

  return 0;
}
