#include <iostream>
using namespace std;

template <typename P>
class Stack {
    public:
          template <typename X> int pop(X pred) const;
};

template <typename P> 
template<typename X>
int Stack<P>::pop(X pred) const{
	return 0;
}

int main() {
	
	Stack<bool> obj;
	char a;
	obj.pop(a);
	
	return 0;
}