#include <iostream>
using namespace std;
 
class InitializeBase
{
public:
    virtual ~InitializeBase() = default;
 
    bool isInit() const
    {
        return isInit_;
    }
 
    void init()
    {
        doInit();
        isInit_ = true;
    }
 
private:
    virtual void doInit() = 0;
 
    bool isInit_ = false;
};
 
class Backdoor : public InitializeBase
{
public:
    void init_twice() { doInit(); doInit(); }
    void doInit() override { std::cout << "Yes, I can" << std::endl; }
};
 
int main() {
	Backdoor bd;
	bd.init();
	bd.init_twice();
	bd.doInit();
}
 

I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwoKY2xhc3MgSW5pdGlhbGl6ZUJhc2UKewpwdWJsaWM6CiAgICB2aXJ0dWFsIH5Jbml0aWFsaXplQmFzZSgpID0gZGVmYXVsdDsKCiAgICBib29sIGlzSW5pdCgpIGNvbnN0CiAgICB7CiAgICAgICAgcmV0dXJuIGlzSW5pdF87CiAgICB9CgogICAgdm9pZCBpbml0KCkKICAgIHsKICAgICAgICBkb0luaXQoKTsKICAgICAgICBpc0luaXRfID0gdHJ1ZTsKICAgIH0KCnByaXZhdGU6CiAgICB2aXJ0dWFsIHZvaWQgZG9Jbml0KCkgPSAwOwoKICAgIGJvb2wgaXNJbml0XyA9IGZhbHNlOwp9OwoKY2xhc3MgQmFja2Rvb3IgOiBwdWJsaWMgSW5pdGlhbGl6ZUJhc2UKewpwdWJsaWM6CiAgICB2b2lkIGluaXRfdHdpY2UoKSB7IGRvSW5pdCgpOyBkb0luaXQoKTsgfQogICAgdm9pZCBkb0luaXQoKSBvdmVycmlkZSB7IHN0ZDo6Y291dCA8PCAiWWVzLCBJIGNhbiIgPDwgc3RkOjplbmRsOyB9Cn07CgppbnQgbWFpbigpIHsKCUJhY2tkb29yIGJkOwoJYmQuaW5pdCgpOwoJYmQuaW5pdF90d2ljZSgpOwoJYmQuZG9Jbml0KCk7Cn0K