#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
  double english, roman, paces;
  int ipaces;

  cin >> english;

  roman = english * 5280.0 / 4854.0;
  paces = roman * 1000.0;
  ipaces = (int)(paces + 0.5);
  cout << ipaces << endl;
  


  return 0;
}