% https://open.kattis.com/problems/peragrams
% 1s
% 1.9 Easy

% Using Picat for some excursions on this.
% For an anagram of a string of
%  * even length: there must be an even occurrences
%    of all chars
%  * odd length: there must be exactly one char
%    with an odd number of occurrences and
%    all the rest must have even occurrences
main :-
  S = read_file_lines().first,
  println(S),
  Ss = S.sort,
  clumped(Ss,Cl),
  writeln(cl=Cl),
  if anagram(S) then
    println(ok)
  else
    println(not_ok)
  end,
  nl.

% 
anagram(S) :-
  Len = S.len,
  println(len=Len),
  H = S.occurrences(),
  println(h=H),
  K = H.values.occurrences(),
  println(k=K),
  M = [Occ mod 2 : Occ in H.values.sort].occurrences,
  println(m=M),
  if Len mod 2 == 1 then
     % Odd length:
     %  - Exactly one occurrenc with odd occurrence
     %  - All the rest must be even occurrence
     M.get(1,0) == 1,
  else
     % Even length:
     % - add öemgths must be even (i.e. no is odd)
     M.get(1,0) == 0
  end,
 
  nl.

occurrences(H) = Occ =>
  Occ = new_map(),
  foreach(E in H)
    Occ.put(E,Occ.get(E,0)+1)
  end.

clumped(Items, Counts) :-
    clump(Items, Counts).
clump([], []).
clump([H|T0], [H-C|T]) :-
    ccount(T0, H, T1, 1, C),
    clump(T1, T).
ccount([H|T0], E, T, C0, C) :-
    E==H,
    !,
    C1 is C0+1,
    ccount(T0, E, T, C1, C).
ccount(List, _, List, C, C).