#include <stdio.h>

int main()
{
  long n;
  scanf("%ld",&n);
  int i;
  i = 0;
  int m;
  m = 100;
  while (1)
  {
    if (m >= n)
    {
      printf("%ld",i);
      break;
    }
    m *= 1.01;
    i++;
  }
  return (0);
}