using System;

using System.Collections.Generic;

​

    public class Program

    {

        static int ParseToInt(string input, ref int position)

        {

            int retVal = 0;

            for (; input[position] >= '0'; ++position)

                retVal = retVal * 10 + input[position] - '0';

            ++position;

            return retVal;

        }

​

        static Dictionary<long, byte> forbidden = new Dictionary<long, byte>(10000);

        static long[] arr1 = new long[10000];

        static byte[] arr2 = new byte[10000];

        static int position;

        static int temp;

        static int length;

        static long number;

​

        public static void Main()

        {

            string input = Console.In.ReadToEnd();

            position = 0;

​

            temp = ParseToInt(input, ref position);

            for (int k = 0; k < temp; k++)

            {

                int numberCount = ParseToInt(input, ref position);

                byte min = 30;

                forbidden.Clear();

​

                for (int i = 0; i != numberCount; ++i)

                {

                    length = position;

                    number = 1;

                    for (; input[position] >= '0'; ++position)

                        number = number * 10 + input[position] - '0';

                    ++position;

​

                    length = position - length;

​

                    if (min > length)

                        min = (byte)length;

                    forbidden.Add(number, 0);

                    arr1[i] = number;

                    arr2[i] = (byte)length;

                }

                bool invalid = false;

                ++min;

                for (int i = 0 ; i != numberCount ; ++i)

                {

                    number = arr1[i];

                    for (int take = min; take <= arr2[i]; ++take)

                    {

                        number = (long) (number * 0.1);

                        if (forbidden.ContainsKey(number))

                        {

                            invalid = true;

                            goto FINISH;

                        }

                    }

                }

                FINISH:

                Console.WriteLine( invalid ? "NO" : "YES");

            }

        }

}