import java.util.ArrayList;
import java.util.Random;


public class Assignment1 {
    public static void main(String[] args) {
        ArrayList<String> couples = new ArrayList<>(10);
        couples.add("X1");
        couples.add("X2");
        couples.add("X3");
        couples.add("X4");
        couples.add("X5");
        couples.add("Y1");
        couples.add("Y2");
        couples.add("Y3");
        couples.add("Y4");
        couples.add("Y5");



        Random r = new Random();
        while (couples.size()>0){
        int i = r.nextInt(couples.size());
        String person1 = couples.remove(i);
        String number1 = person1.split("")[1];
        Boolean isValidFound = false;
        String person2 = null;
            while (!isValidFound) {
                i = r.nextInt(couples.size());
                person2 = couples.get(i);
                String number2 = person2.split("")[1];
                if (!number1.equals(number2)) {
                    isValidFound = true;
                    couples.remove(i);
                }
            }
            System.out.println(person1 + " Buys For " + person2);
        }




        }
    }