#include<iostream>

#include <iomanip>
using namespace std;

int main(){
double a;
	 double ans = 0;
	while (cin >> a) {
		ans += a;
		for (int i =1; i < 10; i++) {
			if (i % 2 == 0) {
				a = a / 3;
				ans += a;
			
			}
			else {
				a = a * 2;
				ans += a;
			
			}
		}
		cout << setprecision(10)<< ans << endl;
	}
	
	
    return 0;
}