#include<iostream>
#include<vector>
#include<string>
#include<array>
#include<cmath>
#include<algorithm>
#include<map>
#include<set>
#include<queue>
#include<numeric>
#include<iomanip>
#include<utility>
#include<cstdlib>
#include<typeinfo>
typedef long long int lint;
#define double long double
using namespace std;
#define INF 1000000005

int main()
{
double d;
std::cin >> d;
std::cout << fixed << setprecision(12)<< d * 1.08000000000000 << std::endl;
return 0;
}