Tien taxi

#include <iostream>
using namespace std;
int main(){
    int n;
    cout << "Nhap so km: ";
    cin >> n;
    int tien = 0;
    n -= 1;
    tien += 5000;
    if (n > 0){
        if (n + 1 >= 5){
            tien += 4500 * 4;
            n -= 4;
        }
        else{
            tien += 4500 * n;
            n = 0;
        }
    }
    if (n > 0){
        if (n + 5 >= 6){
            tien += 3500 * n;
        }
    }
    if (n >= 120){
        tien *= 0.9;
    }
    cout << "Tien: " << tien;
    system("pause");
    return 0;
}