#include <iostream>
using namespace std;
int main(void){
   double a;
   
   while(cin>>a){
       double b=0,c=0;
       b=a;
       c+=a;
       for(int i=2;i<=10;i++){
           if(i%2==0) b*=2;
           else if(i%2==1) b/=3;
           c+=b;
       }
       cout<<fixed<<c<<endl;
       
   }
   
    return 0;
}

