#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <complex>
using namespace std;

#define REP(i,n) for(int i=0;i<(int)n;++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()

int main() {
  double a;
  while(cin>>a){
    double ans = a;
    for(int i=2;i<=10;i++) {
      if (i%2==1)
        a/=3;
      else
        a*=2;
      ans += a;
    }
    printf("%.8lf\n",ans);
  }
}