#include <iostream> #include <iomanip> using namespace std; int main() { int distance; cin >> distance; double cost; if (distance <= 2) { cost = 6.0; } else if (distance <= 10) { cost = 6.0 + (distance - 2) * 1.8; } else { cost = 6.0 + 8 * 1.8 + (distance - 10) * 2.7; // 或者 cost = 20.4 + (distance - 10) * 2.7; } cout << cost << endl; return 0; }