#include <bits/stdc++.h>
using namespace std;

int main()
{
  double n;

  while (cin >> n){
    double sum = 0;
    sum += n;
    for (int i = 2; i <= 10; i++){
      if (i % 2 == 0){
        n *= 2;
      }
      else {
        n /= 3;
      }
      sum += n;
    }
    printf("%.8f\n", sum);
  }

  return (0);
}