type lineType = ANIMALS | NUMBERS

let processLine (state, animals, numbers) line =
    match line, state with
    | "ANIMALS", _ -> (ANIMALS, animals, numbers)
    | "NUMBERS", _ -> (NUMBERS, animals, numbers)
    | _, ANIMALS -> (state, line::animals, numbers)
    | _, NUMBERS -> (state, animals, line::numbers)

let (_, animals, numbers) =
    System.IO.File.ReadAllLines("input.txt") |> Seq.fold processLine (ANIMALS, [], [])

let groupList = Set.of_list >> Set.to_list
let sortedAnimals = animals |> groupList |> List.sort
let sortedNumbers = numbers |> groupList |> List.sort

printf "There are %d animals which are: %A\r\n" (List.length sortedAnimals) sortedAnimals
printf "There are %d numbers which are: %A\r\n" (List.length sortedNumbers) sortedNumbers

System.Console.ReadLine() |> ignore