using System;

using System.Linq;

using System.Collections;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Dictionary<char,int>count=new Dictionary<char,int>();

        string alphabet = "abcdefghijklmnopqrstuvwxyz";

        string sentence = "This is an example bla bla blA";

        foreach (char c in alphabet)

        {

            count.Add(c,sentence.ToLower().Count(ch => ch == c));

            Console.WriteLine(c+"="+count[c]);

        }

    }

}