/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Main {

    private static String category = "electronic trading system";
    public static void main(String[] args) {
        Main system = null;
        System.out.println(system.category);
    }
}