#include <stdio.h>

int main(void){
  unsigned long long int x=0;
  unsigned long long int y=100;
  unsigned long int cnt=0;
  scanf("%d", &x);
  while(y < x){
    y += y*0.01;
//    printf("%d\n",y);
    cnt += 1;
  }
  printf("%d", cnt);
  return 0;
}