#include <iostream>
#include <stdio.h>
#include <cmath>

using namespace std;
class china_majan {
public:
    int han;
    int hu;
    virtual int ko(){
        return (this->han*this->hu*3);
    }
    virtual int oya(){
        return (this->han*this->hu*4);
    }
};

class japan_majan : public china_majan {
    int ko() override {
        return (pow(2,this->han+2)*this->hu*4);
    }
    int oya() override {
        return (pow(2,this->han+2)*this->hu*6);
    }
};
int main() {
    printf("&&\n");
    std::cout << "Hello world!" << std::endl;
    return 0;
}