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

namespace Set
{
    class Program
    {
       static public int Count(int[] A, int[] B,string f)
        {
          int  count = 0;
            for (int i = 0; i < A.Length; i++)
            {
                for (int j = 0; j < B.Length; j++)
                {
                    if (A[i] == B[j]) { count++; }
                }
            }
            if (count >= B.Length)
            {
                Console.WriteLine(f);
                return 0;
            }
            return 0;
        }
        static void Main(string[] args)
        {
            Console.WriteLine("Enter A");
            string[] tokensA = Console.ReadLine().Split();
            int[] A = new int[tokensA.Length];
            Console.WriteLine("Enter B");
            string[] tokensB = Console.ReadLine().Split();
            int[] B = new int[tokensB.Length];
            Console.WriteLine("Enter C");
            string[] tokensC = Console.ReadLine().Split();
            int[] C = new int[tokensC.Length];
            Console.WriteLine("Enter D");
            string[] tokensD = Console.ReadLine().Split();
            int[] D = new int[tokensD.Length];
            for (int i = 0; i < tokensA.Length; i++)
            {
                A[i] = int.Parse(tokensA[i]);
            }
            for (int i = 0; i < tokensB.Length; i++)
            {
                B[i] = int.Parse(tokensB[i]);
            }
            for (int i = 0; i < tokensC.Length; i++)
            {
                C[i] = int.Parse(tokensC[i]);
            }
            for (int i = 0; i < tokensD.Length; i++)
            {
                D[i] = int.Parse(tokensD[i]);
            }
            string[] h = { "AB", "AC", "AD", "BA", "BC", "BD", "CA", "CB", "CD", "DA", "DB", "DC" };
            int countAB =  Count(A, C,h[0]);
            int countAC =  Count(A, B, h[1]);
            int countAD = Count(A, D, h[2]);
            int countBA =  Count(B, A, h[3]);
            int countBC =  Count(B, C, h[4]);
            int countBD = Count(B, D, h[5]);
            int countCA =  Count(C, A, h[6]);
            int countCB =  Count(C, B, h[7]);
            int countCD = Count(C, D, h[8]);
            int countDA =  Count(D, A, h[9]);
            int countDB = Count(D, B, h[10]);
            int countDC = Count(D, C, h[11]);
            Console.ReadLine();
        }
    }
}