{
 Definition: Permutation
 A permutation is an arrangement of n objects, arranged in groups of size r
 without repetition where order is important.
 P(n,r) = n! / (n-r)!
 Example: Find all two-letter permutations of the letters "ABC"
 n = ABC
 r = 2
 Output: AB AC BA BC CA CB
}

 {
 Definition: Permutation
 Eine Permutation ist eine Anordnung von n Objekten ohne Wiederholung.
 Dabei spielt die Reihenfolge der Elemente in den Mengen keine Rolle.
 P(n,r) = n! / (n-r)!
 Beispiel: Finde alle 2-Buchstaben Kombinationen von "ABC"
 n = ABC
 r = 2
 Ergebnis: AB AC BA BC CA CB
}

 {
 The following is a console Program:
 Choose File, New, Console Application
}

  program Permute;
 {$APPTYPE CONSOLE}
 uses SysUtils;
 var
  R, Slen: Integer;
 procedure P(var A: string; B: string);
 var
  J: Word;
  C, D: string;
 begin
  { P(N,N) >> R=Slen }
  if Length(B) = SLen - R then
  begin
  Write(' {' + A + '} '); {Per++}
  end
  else
  for J := 1 to Length(B) do
  begin
  C := B;
  D := A + C[J];
  Delete(C, J, 1);
  P(D, C);
  end;
 end;
 var
  Q, S, S2: string;
 begin
  S := ' ';
  S2 := ' ';
  while (S <> '') and (S2 <> '') do
  begin
  Writeln('');
  Writeln('');
  Write('P(N,R) N=? : ');
  ReadLn(S);
  SLen := Length(S);
  Write('P(N,R) R=? : ');
  ReadLn(S2);
  if s2 <> '' then R := StrToInt(S2);
  Writeln('');
  Q := '';
  P(Q, S);
  end;
 end.