#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
#define OP(m) cout << m << endl
typedef long long ll;
typedef unsigned long long ull;

int main()
{
    double a;
    while (cin >> a)
    {
        double be = a, sum = a;
        for (int i = 2; i <= 10; i++)
        {
            if (i % 2 == 0)
            {
                sum += be * 2;
                be *= 2;
            }
            else
            {
                sum += be / 3;
                be = be / 3;
            }
        }
        printf("%.8f\n", sum);
    }
    return 0;
}
