#include<stdio.h>
#include<stdlib.h>
int main()
{
  long X,i,gaku;
  scanf("%ld",&X);
  gaku=100;
  for(i=1;i<=1000000000000000000;i++)
  {
   gaku=gaku+gaku/100;
   if(gaku>=X)
   {
     printf("%ld",i);
     exit(0);
   } 
  }
}
   