using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        task();

    }

    private static void task()

    {

        int[] h = {1,6,7,8,4,12};

        h = h.OrderBy(x=>x).ToArray();

        List<Tuple<int,int>> alloc = new List<Tuple<int,int>>();

        for(int i=0,j=h.Count()-1;i<j; i++,j--)

        {

            alloc.Add(Tuple.Create<int,int>(h[i],h[j]));

        }

        print( alloc);

    }

    private static void print(List<Tuple<int,int>> t)

    {

        foreach(var x in t)

        {

            Console.WriteLine(x.Item1 + " - " + x.Item2 );

        }

    }

}