#include <iostream>
#include <cstdlib>
#include <stack>
#include <queue>
using namespace std;

int main()
{
	stack<int> s;   //Construct an empty stack.

	s.push(10);
	s.push(20);
	s.push(30);

	cout << s.top() << "\n";
	s.pop();

	cout << s.top() << "\n";
	s.pop();

	cout << s.top() << "\n";
	s.pop();

	cout << "\n";

	queue<int> q;   //Construct an empty queue.

	q.push(10);
	q.push(20);
	q.push(30);

	cout << q.front() << "\n";
	q.pop();

	cout << q.front() << "\n";
	q.pop();

	cout << q.front() << "\n";
	q.pop();

	cout << "\n" << q.empty() << "\n";

	return EXIT_SUCCESS;
}