(import std.String :toLower :find :asciiLowercase)
(import std.List)
(import std.Dict)
(import std.IO)

(let countLetters (fun (s) {
  (let counts (dict))
  (list:forEach s
    (fun (c) {
      (set c (toLower c))
      (if (!= -1 (find asciiLowercase c))
        (dict:add counts c (if (nil? (dict:get counts c)) 1 (+ 1 (dict:get counts c))))) }))
  counts }))

(print (countLetters (io:readFile "f.txt")))