count = {}
("a".."z").to_a.each do |elem|
  count[elem] = 0
end
while line = gets
  line.chomp!
  line.downcase!
  line.split(//).map{ |e|
    count[e] += 1 if count.key?(e)
  }
end
count.each do |key,value|
  puts "#{key} : #{value}"
end