count = Hash.new
ARGF.each do |line|
  line.each_char do |c|
    c = c.downcase
    count[c] = 0 unless count[c]
    count[c] += 1
  end
end
('a'..'z').each do |s|
  count[s] ? ( puts "#{s} : #{count[s]}" ) : ( puts "#{s} : 0" )
end