using System;
class RandomizeTheNumbers1ToN
{
    static void Main()
    {
        int n;
        Console.Write("Enter an integer: ");
        while (!int.TryParse(Console.ReadLine(), out n) || n <= 0)
        {
            Console.WriteLine("Invalid input.Try again.");
            Console.Write("Enter an integer: ");
        }

        bool[] numberPrinted = new bool[n + 1];
        int numberToPrint;
        Random randomGenerator = new Random();
        for (int i = 1; i <= n; i++)
        {
            numberToPrint = randomGenerator.Next(1, n + 1);
            if (!numberPrinted[numberToPrint])
            {
                Console.Write("{0} ", numberToPrint);
                numberPrinted[numberToPrint] = true;
            }
            else
            {
                i--;
            }
        }
        Console.WriteLine();
    }
}