using System;

​

public class Program

{

    public static void Main()

    {

        int[] a = new int[12];

        int[] b = new int[12];

        for (int i = 1; i < a.Length-1; i++)

        {

            b[i] = i;

        }

        for (int i = 1; i < a.Length-1; i++)

        {

            Console.WriteLine("Enter your preferred room partner number");

            a[i] = int.Parse(Console.ReadLine());

        }

        for (int t = 1; t < a.Length-1; t++)

        {

            if (a[t] == b[a[t]] && b[t] == a[b[a[t]]])

            {

                Console.WriteLine("student " + a[t] + " chose student " + a[b[a[t]]] + " and student " + b[t] + " chose student " + b[a[t]]);

            }

        }

    }

}