#include<iostream>
#include <iomanip>

using namespace std;
int main()
{
  double s;
  cin>>s;
  double sum=s;
  for(int i=2;i<=10;i++)
    {
      if(i%2==0)
	s*=2;
      else
	s/=3;
      sum+=s;
    }
  cout<<setprecision(10);
  cout<<sum<<endl;
}