#include <stdio.h>

int main()
{
  double A = 100.0;
  long long int x;
  double X;
  int i;
  int j;
  long long int temp;
  scanf("%lf", &X);
  
  for(i = 1; /**/ ; ++i){
    A = 100.0;
    for(j = 0; j < i; ++j){
      A *= 1.01;
      temp = (long long int)A;
      A = (double)temp;
    }
    //printf("%lf, %lf\n", A, X);
    if(A >= X){
      printf("%d\n", i);
      return 0;
    }
  }
}