count_ary = []
for i in "a".."z" do 
    count_ary.push([i, 0])
end

while (line_input = gets) do

    line = line_input.downcase

    line.chars{|ch|
        for i in 0..25 do
            if ch == count_ary[i][0] then
                count_ary[i][1] += 1
            end
        end
    }
end

26.times{|i|
    puts count_ary[i].join(" : ")
}
