keys = ('a'..'z').to_a
values = Array.new(26){0}
alpha_hash = Hash[*[keys, values].transpose.flatten]
s = gets.strip
until s.nil?
	s.chars do |c|
		if c =~ /[a-zA-Z]/
			c.downcase!
			alpha_hash[c] +=  1 
		end
	end
	s = gets
end

alpha_hash.each do |key, value| 
	puts "#{key} : #{value}"
end
