using System;

namespace Matrix
{
    class Program
    {
        static void Main(string[] args)
        {
            int a = int.Parse(Console.ReadLine());
            int b = int.Parse(Console.ReadLine());
            int c = int.Parse(Console.ReadLine());
            int d = int.Parse(Console.ReadLine());
            while (true)
            {
                for (int x1 = a; x1 <= b; x1++)
                {
                    for (int x2 = a; x2 <=b; x2++)
                    {
                        for (int x3 = c; x3 <= d; x3++)
                        {
                            for (int x4 = c; x4 <= d; x4++)
                            {
                                if (x1+x4==x2+x3&&x1!=x2&&x4!=x3)
                                {
                                    Console.WriteLine($"{x1}{x2}");
                                    Console.WriteLine($"{x3}{x4}");
                                    Console.WriteLine();
                                }
                            }
                        }
                    }
                }

            }

        }
    }
}