#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS

#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <list>
#include <utility>
#include <numeric>

using namespace std;
typedef long long llong;
typedef unsigned long long ullong;

const ullong MOD = 1000000000 + 7;

int main()
{
	double a;
	for (; cin >> a;)
	{
		double a0 = a;
		double sum = a;
		for (int i = 2; i <= 10; i++)
		{
			if (i % 2 == 0)
			{
				a0 = a * 2;
				sum += a0;
			}
			else
			{
				a0 = a / 3;
				sum += a0;
			}
			a = a0;
		}

		cout << fixed << setprecision(8) << sum << endl;
	}
}
