using System;

using System.Globalization;

using System.Collections.Generic;

using System.Xml;

using System.Xml.Linq;

​

using System.Linq;

​

public class Program{

    public static void Main() {

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            var letterfill = new letters();

            Console.WriteLine(letterfill.GenerateLetters(100));

    }

    public class letters{

        public letters() {}

​

        public string GenerateLetters(int x) {

            Random rd = new Random();

            int[]array = new int[x];

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          const string chars = "ABCDEFGHIJKLMNOPQRSTUVW";

    return new string(Enumerable.Repeat(chars, array.Length)

        .Select(s => s[rd.Next(s.Length)]).ToArray());

​

      }

    }

}

​

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​