#include <stdio.h>
int main(){
  int x;
  scanf("%d",&x);
  int i,y;
  double m;
  m=100;
  for(i=1;i<=x-100;i++){
    m=m*1.01;
    if(m>=x){
      y=i;
      break;
    }
  }
  printf("%d\n",y);
  return 0;
}