#include <iostream>
#include <cstdlib>
using namespace std;
#include "stack.h"

int main()
{
	cout << "To hire a person, type their social security number.\n"
		"To fire the most recently hired person, type a zero.\n"
		"To quit, type a negative number.\n";

	::stack s;   //Call the constructor for s with no arguments.

	for (;;) {
		int ss;            //uninitialized variable
		cin >> ss;
		if (ss < 0) {      //quit
			break;
		}

		if (ss > 0) {      //hire
			s.push(ss);
		} else {           //fire
			cout << "Firing number " << s.pop() << ".\n";
		}
	}

	return EXIT_SUCCESS;   //Call the destructor for s.
}