#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using pii = pair<int, int>;

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  
  double a;
  while (cin >> a) {
    double ans = a;
    for (int i = 2; i <= 10; i++) {
      if (i & 1) a /= 3;
      else a *= 2;
      ans += a;
    }
    cout << ans << endl;
  }

  return 0;
}
