#include<iostream.h>

class A{

public:

    virtual void pr(){cout<<"1"<<endl;}

};

class B:public A{

    void pr(){cout<<"2"<<endl;}

};

void p1(A&a)

{a.pr();}

void p2(A a)

{a.pr();}

void main(){

     B b;

     p1(b);

     p2(b);

}