#include <iostream>
using namespace std;

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