#include <iostream>
#include <csdio>
using namespace std;

int main(){
  double s[10],num,sum;

    while(cin >> num){
      s[0] = num;
      sum = 0;

      for(int i = 0 ; i < 10 ; i++){
        if((i+1)%2 == 0) s[i] = s[i-1] *2.0;
        else s[i] = s[i-1] / 3.0;
      }

      for(int i = 0 ; i < 10 ; i++) sum += s[i];
      printf("%.8f\n" ,sum);
  }

  return 0;
}