#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    ll D;
    std::cin >> D;

    ll rest = D * 8 % 100;
    if(rest < 10){
        std::cout << (D + D * 8 / 100) << ".0" << (D * 8 % 100) << std::endl;        
    }else{
        std::cout << (D + D * 8 / 100) << "." << (D * 8 % 100) << std::endl;
    }
}