#include <iostream> 
#include <cstdio> 
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; 
}