Problem 4 – Odd Number

//You are given a list of N integer numbers all but one of which appears an even number of times.
//Write a program to find the one integer which appears an odd number of times.
//Input
//The input data is being read from the console.
//The number N is written on the first input line.
//On each of the following N lines there is one integer number written – the consequent number from the given list of numbers.
//The input data will always be valid and in the format described. There is no need to check it explicitly.
//Output
//The output data must be printed on the console.
//On the only output line you must print the integer from the list which appears an odd number of times.
//Constraints
//•   N will be positive odd integer number between 1 and 99 999, inclusive.
//•   All of the numbers in the list will be integer numbers between -9 223 372 036 854 775 808
//and 9 223 372 036 854 775 807, inclusive.
//•   Always only one answer will exists and will be unambiguous.
//•   Allowed working time for your program: 0.25 seconds.
//•   Allowed memory: 16 MB.


using System;

class Program
{
    static void Main()
    {
        string input = Console.ReadLine();
        int N = int.Parse(input);
        long number = 0;
        long result = 0;
        if (N == 1)
        {
            input = Console.ReadLine();
            number = long.Parse(input);
            Console.WriteLine(number);
        }
        else
        {
            for (int i = 0; i < N; i++)
            {
                input = Console.ReadLine();
                number = long.Parse(input);

                result ^= number;
            }
            Console.WriteLine(result);
        }
    }
}