#include<iostream>
using std::cout;

class Input {

 public:
 	virtual void in(int)=0;

};

class Output {

 public:
 	virtual int out()=0;
};

class UnsecuredIO : public Input, public Output {
int buff;
	void in(int val) { buff=val;}
	int out() { return buff;}
};



int main () {
 
 UnsecuredIO *u = new UnsecuredIO();

 Input *in = u;
 Output *out = u;

 in->in(25);
 int x = out->out();
 cout<<x << "\n";


}