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)

k = ('a'..'z').to_a
v = Array.new(26, 0)
h = {}
k.zip(v).each{|kk, vv| h[kk] = vv}
while line = gets
  line.chomp.split('').each do |c|
    next if c == ' '
    next if c == '.'
    c.downcase!
    h[c] += 1
  end
end
h.each do |key, val|
  print "#{key} : #{val}\n"
end