#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

ll d;
int main() {
  cin >> d;
  if (d * 108 % 100 == 0) cout << d * 108 / 100 << endl;
  else cout << fixed << setprecision(2) << (ld)d * 108 / 100 << endl;
  return 0;
}