Problem:
Counting Characters

Write a program which counts and reports the number of each alphabetical letter. Ignore the case of characters.

Input

A sentence in English is given in several lines.

Output

Prints the number of alphabetical letters in the following format:

a : The number of 'a'
b : The number of 'b'
c : The number of 'c'
.
.
z : The number of 'z'

Constraints

The number of characters in the sentence < 1200

Sample Input

This is a pen.

Sample Output

a : 1
b : 0
c : 0
d : 0
e : 1
f : 0
g : 0
h : 1
i : 2
j : 0
k : 0
l : 0
m : 0
n : 1
o : 0
p : 1
q : 0
r : 0
s : 2
t : 1
u : 0
v : 0
w : 0
x : 0
y : 0
z : 0

Solution in C# (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace AtCoder
{
	class Program
	{
		static void Main(string[] args)
		{
			var Instance = new Question();
			Instance.Exec();
		}
	}

	public class Question
	{
		public void Exec()
		{
			string str = "";
			string tempStr = "temp";
			while (string.IsNullOrWhiteSpace(tempStr) == false) {
				tempStr = Console.ReadLine();
				if (string.IsNullOrWhiteSpace(tempStr)) {
					break;
				}

				str += tempStr.ToLower();
			};

			//Console.WriteLine(str);
			List<string> alphabets = new List<string>();
			char[] chars = str.ToArray();
			for (char alpha = 'a'; alpha <= 'z'; ++alpha) {
				char[] finds = Array.FindAll(chars, item => item == alpha);
				int sum = finds.Length;
				alphabets.Add($"{alpha.ToString()} : {sum}");
			}

			for (int i = 0; i < alphabets.Count; ++i) {
				Console.WriteLine($"{alphabets[i]}");
			}

			Console.ReadKey();
		}
	}
}