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 Ruby (judge verdict: Runtime Error)

#lines = [
#        "This is a pen."
#]

lines = $stdin.read.split("\n")

lines.each do |l|

        array = l.downcase!.each_codepoint.to_a
        sum_h = (96..122).to_a.map{ |c| [c, 0]}.to_h
        array.each{|i| sum_h[i] += 1 unless sum_h[i].nil? }

        sum_h.sort.select{|k,v| 96 < k && k < 123 }.map do |k,v|
                puts "#{k.chr} : #{v}"
        end
end