#include <bits/stdc++.h>
using namespace std;
int main(void) {
    double a,sum;
    sum=0;
    std::deque<double> deq;
    while (cin>>a) {
        deq.emplace_back(0);
        deq.emplace_back(a);
        for (int i=2;i<11;i++) {
            if (i%2==0) {
                deq.emplace_back(deq[i-1]*2);
            } else {
                deq.emplace_back(deq[i-1]/3);
            }
        }
        for (int j=0;j<deq.size();j++) {
            sum=sum+deq[j];
        }
        printf("%.8f",sum);
        cout<<endl;
        sum=0.0;
        deq.clear();
    }
}
