#include <iostream>
#include <cstdio>

using namespace std;

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

    return 0;
}