using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public static void Main()
//lower case
PrintLetters('a');
//upper case
PrintLetters('A');
Console.WriteLine("--done--");
}
private static void PrintLetters(char start)
Enumerable
.Range(start, 26)
.Select(i => (char)i)
.ToList()
.ForEach(c => Console.WriteLine(c));