#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(){

  double n;
  while(cin >> n){
    double sum=n;
    for(int i=2;i<=10;i++){
      if(i%2 == 0){
        n *= 2.;
      }
      else{
        n /= 3.;
      }
      sum += n;
    }
    cout << sum << endl;
  }
  return 0;
}