#include "stdio.h"
#include <iostream>
using namespace std;

/** Problem0055 : Sequence **/
int main()
{
	double input, sum, old;
	
	while (cin >> input) {
		sum = input;
		old = input;
		for (int i=2; i<=10; i++) {
			if (i%2==0) {
				sum+=old*2;
				old=old*2;
			} else {
				sum+=old/3;
				old=old/3;
			}
		}
		printf("%.8lf\n", sum);
	}
	
	return 0;
}