using System;

using System.Linq;

using System.Numerics;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Eanean sodales justo et Enim ornare, a congue lacus commodo".OccurrenceCount('e'));

        var myNumber = BigInteger.Parse("17272838119191929838299111");

        Console.WriteLine(myNumber.CountDigitOccurrences('1'));

        Console.WriteLine(Adder.AddEm(7,5));

    }

}

​

public static class StringExtensions

{

    public static long OccurrenceCount(this string text, char letter)

    {

        return text.Count(t => t == letter);

    }

}

​

public static class BigIntegerExtensions

{

    public static long CountDigitOccurrences(this BigInteger number, char digit)

    {

        int digitAsInt;

        if (!int.TryParse(digit.ToString(), out digitAsInt))

        {

            throw new ArgumentException("Digit must be a numeric character.");

        }

        return number.ToString().OccurrenceCount(digit);

    }

}

​

public static class Adder

{

    public static long AddEm(params int[] numbers)

    {

        return numbers.Sum();

    }

    public static long AddEm(params long[] numbers)

    {

        return numbers.Sum();

    }

    public static decimal AddEm(params decimal[] numbers)

    {

        return numbers.Sum();

    }

    public static double AddEm(params double[] numbers)

    {

        return numbers.Sum();

    }

}

​