#include <iostream>
using namespace std;

int main(){
    double n,s[10];
    
    while(cin >> n){
        double ans = 0.0;
        s[0] = n;
        
        for(int i = 1 ; i < 10 ;i++){
            if((i+1)%2==0) s[i] = 2.0*s[i-1];
            else s[i] = s[i-1] / 3.0;
        }
        
        for(int i = 0 ; i < 10 ; i++) ans += s[i];
        cout << ans << endl;
    }

    return 0;
}