#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<queue>
#include<vector>
#include<map>
#include<list>
#include<cctype>
#include<climits>
#include<bitset>

using namespace std;

signed main()
{
	double N;
	cin >> N;
	printf("%.16lf", N * 108 / 100);
	return 0;
}