#include <iostream> using namespace std; int main() { int s; cin >> s; double cost; if (s <= 2) { cost = 6; } else if (s <= 10) { cost = 6 + (s - 2) * 1.8; } else { cost = 6 + 8 * 1.8 + (s - 10) * 1.8 * 1.5; } cout << cost << endl; return 0; }