#include <bits/stdc++.h> using namespace std; int main() { double a, b; cin >> a; if (a <= 2) { a = a - 2; b = b + 6; } if (a > a && a <= 10) { a = a - 10; b = b + 10 * 1.8; } if (a > 10) { double c; c = c + 1.8 + 1.8 / 2; b = b + (a - 10 - 2) * c; } cout << b; }