#include <iostream>
using namespace std;

class A{
public:
	A(){};
	~A(){};
	virtual void foo(int a, int b) = 0;
};
class B : public A
{
public:
	B(){};
	~B(){};
	void foo(int a){};
};

int main() {
	// your code goes here
	B b;
	b::A::foo();
	return 0;
}