#include<stdio.h>

int main()
{

  unsigned long long a = 100;
  unsigned long long x;
  scanf("%lld",&x);
  int year = 1;

//    printf("%d",x);
  while(1){
    a = a + a*0.01;
    if(a >= x){
      printf("%d",year);
      return 0;
    }
    year ++;
//    printf("%d %d\n",a,year);
  }

}

