Need to remove duplicate values from C# program

Question

I need some help with a C# program that i am creating. So in this scenario i am inputting duplicate values into the program. For Example, a,b,b,c,c.
The exercise is that

Answer 1

Use Any linq expression to validate duplicates. char.TryParse will validates input and returns true when succeeded.

public static void Main()
{
    char[] arr = new char[5];

    //User input
    Console.WriteLine("Please Enter 5 Letters only: ");

    for (int i = 0; i < arr.Length; i++)
    {
         char input;

        if(char.TryParse(Console.ReadLine(), out input) && !arr.Any(c=>c == input))
        {           

            arr[i] = input;
        }
        else
        {
            Console.WriteLine( "Error : Either invalid input or a duplicate entry.");
            i--;
        }
    }

    Console.WriteLine("You have entered the following inputs: ");
    //display
    for(int i = 0; i

Working Code