def isalpha(c)
    o = c.ord
    return ('a'.ord <= o && o <= 'z'.ord) || ('A'.ord <= o && o <= 'Z'.ord) 
end

cnt = [0] * 26
while gets do
    $_.chars.each do |ch|
        if isalpha(ch)
            cnt[ch.downcase.ord-'a'.ord] += 1
        end
    end
end

cnt.each_with_index {|c, i| puts ('a'.ord+i).chr + " : " + c.to_s }

