OddNumber-vaeiant1

using System;



class Program
{
    static void Main()
    {
        int numbers = int.Parse(Console.ReadLine());
        int j = 0;
        long[] values = new long[numbers];
        int[] count = new int[numbers];


        for (int i = 0; i < numbers; i++)
        {
            values[i] = long.Parse(Console.ReadLine());
            for (int k = 0; k <= i; k++)
            {
                if (values[i] == values[k])
                {
                    count[i]++;
                    count[k]++;
                }
            }

        }

        for (j = 0; j < numbers; j++)
        {
            if (count[j] % 2 == 0)
            {
                Console.WriteLine(values[j]);
                break;
            }
        }

    }
}