#include <iostream>
#include <cstdio>
using namespace std;
int main(){
  double n;
  while( cin >> n ){
    double a[10];
    double sum = n;
    a[0] = n;
    for(int i = 1; i < 10; i++){
      // even
      if(i % 2 == 1)
	{
	  a[i] = a[i-1] * 2;
      }
      // odd
      else
	{
	  a[i] = a[i-1]/3;
      }
      sum += a[i];
    }
    printf("%.9lf\n", sum);
  }

  return 0;
}