#include <bits/stdc++.h>
using namespace std;
using ld = long double;
ld N;
void input() { cin >> N; }
void solve() { cout << N * 1.08 << endl; }
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(3);
  input();
  solve();
}