#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
#include<sstream>
#include<iterator>
#include<list>

using namespace std;

typedef  long long int lint;

#define rep(i, n) for (lint i = 0; i < n; i++)
#define sort(v) sort((v).begin(), (v).end())
#define reverse(v) reverse((v).begin(), (v).end())
#define upper(v,hoge) upper_bound(v.begin(),v.end(),hoge)
#define lower(v,hoge) lower_bound(v.begin(),v.end(),hoge)
#define mp make_pair
#define IP pair<int,int>
#define enld endl

int main() {
	double a;
	while (cin >> a) {
		vector<double>A(10);
		A[0] = a;
		for (lint i = 1; i < 10; i++) {
			if (i % 2 == 0) {
				A[i] = A[i - 1] / 3.0;
			}
			else {
				A[i] = A[i - 1] * 2.0;
			}
		}
		double sum = 0;
		rep(i, 10) {
			sum += A[i];
		}
		cout <<fixed<<setprecision(10)<< sum << endl;
	}
}
