using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var ints = new[] {2, 0, 3};

        var result = ints.SelectMany((i, index) => {

            var letter = ((char)(65 + index)).ToString();

            var letterArray = Enumerable.Repeat(letter,i);

            return letterArray;

        });

        // shorter:

        result = ints.SelectMany((i, index) => Enumerable.Repeat(((char)(65 + index)).ToString(),i));

        foreach(var letter in result) {

            Console.WriteLine(letter);  

        }

    }

}