using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;

class StuckNumbers
{
    static void Main(string[] args)
    {

        int k = int.Parse(Console.ReadLine());
        string[] arrayNumbers = new string[k];
        arrayNumbers = Console.ReadLine().Trim().Split(' ').ToArray();
        bool isTrue = false;

        for (int aIndex = 0; aIndex < arrayNumbers.Length; aIndex++)
        {
            for (int bIndex = 0; bIndex < arrayNumbers.Length; bIndex++)
            {
                for (int cIndex = 0; cIndex < arrayNumbers.Length; cIndex++)
                {
                    for (int dIndex = 0; dIndex < arrayNumbers.Length; dIndex++)
                    {
                        string a = arrayNumbers[aIndex];
                        string b = arrayNumbers[bIndex];
                        string c = arrayNumbers[cIndex];
                        string d = arrayNumbers[dIndex];

                        if (a != b && a != c && a != d && b != d && b != c && c != d)
                        {
                            string firstPart = a + b;
                            string secondPart = c + d;
                            if (firstPart == secondPart)
                            {
                                Console.WriteLine("{0}|{1}=={2}|{3}", a, b, c, d);
                                isTrue = true;
                            }
                        }
                    }
                }
            }
        }
        if (!isTrue)
        {
            Console.WriteLine("No");
        }
    }
}