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)

key = [*'a'..'z']
value = Array.new(key.size, 0)
ary = [key,value].transpose
h = Hash[*ary.flatten]
sentences = []
while line = gets
  sentences.push line.chomp.downcase!.split("")
end
sentences.flatten!
sentences.each do |s|
  h[s] += 1 if h.has_key?(s)
end
h.each do |i, j|
  puts "#{i} : #{j}"
end