#include <iostream>

using namespace std;

int main(void) {
    double a, s;
    while (true) {
        cin >> a;
        s = a;
        if (cin.eof()) break;;
        for (int i = 2; i <= 10; i++) {
            if (i % 2 == 0) {
                a = a * 2;
                s += a;
            } else {
                a = a / 3;
                s += a;
            }
        }
        cout << s << endl;
    }
    return 0;
}