#include <iostream> #include <iomanip> // 用于控制输出格式 using namespace std; int main() { int distance; cin >> distance; double cost = 0.0; if (distance <= 2) { cost = 6; } else if (distance <= 10) { cost = 6 + (distance - 2) * 1.8; } else { cost = 6 + (10 - 2) * 1.8 + (distance - 10) * 2.7; } // 输出保留一位小数 cout << fixed << setprecision(1) << cost << endl; return 0; }