#include<stdio.h> 
int main() { 
  unsigned long long int x,y=0,i=100; 
  scanf("%llu",&x); 
  while(1){ 
    i=i+(i*0.01); 
    y++; 
    if(i>=x){ break; } }
    printf("%llu\n",y);

    return 0; } 
