#include<iostream>
#include<vector>

using namespace std;

int main(){
    double n = 0;
    vector<double> vn(11,0);
    cin >> vn[1] ;
    for(int i = 2; i < 11;++i){
        if(i % 2 == 0){
            vn[i] = vn[i-1] * 2;
        }
        else{
            vn[i] = vn[i-1] / 3;
        }
        n += vn[i] ;
    }
    printf("%.12f\n", n + vn[1]);
    return 0;
}