count = Hash.new

('a'..'z').each do |key|
  count[key] = 0
end

while s = gets
  s = s.chomp.downcase.chars
  s.each do |s_i|
    if 'a' <= s_i && s_i <= 'z'
      count[s_i] += 1
    end
  end
end


('a'..'z').each do |key|
  puts "#{key} : #{count[key]}"
end

