import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*; 

public class One extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

	response.setContentType("text/html"); 
	HttpSession session = request.getSession(); 

        String a = (String)session.getAttribute("a"), 
               b = (String)session.getAttribute("b"), 
               message = (String)session.getAttribute("message"); 

        if (message == null) {
          a = (int)(Math.random() * 100 - 50) + ""; 
          b = (int)(Math.random() * 100 - 50) + ""; 
          message = "What is " + a + " + " + b + "?"; 
        } else { 
          String answer = request.getParameter("answer"); 
          int user = Integer.parseInt(answer); 
          if (Integer.parseInt(a) + Integer.parseInt(b) == user) {
            message = "The answer was correct. <p>"; 
          } else {
            message = "Wrong answer. <p>"; 
          } 

          a = (int)(Math.random() * 100 - 50) + ""; 
          b = (int)(Math.random() * 100 - 50) + ""; 
          message += "What is " + a + " + " + b + "?"; 
          
        } 

        session.setAttribute("a", a); 
        session.setAttribute("b", b); 
        session.setAttribute("message", message); 

	PrintWriter out = response.getWriter(); 

	out.println(message); 

    }
}