#include <iostream>
#include <iomanip>

using namespace std;

int main() {
  long double a;
  while (cin >> a) {
    long double sum = a;
    for (int i = 2; i <= 10; ++i) {
      if ((i % 2) == 0)
        a = a * 2;
      else
        a = a / 3;
      sum += a;
    }
    cout << fixed;
    cout << setprecision(8) << sum << endl;
  }
}
