pascal: problem s retazcom

program Retez_6;
const
  SPACE = ' ';
var
  OrigStr    : string;
  ResultStr  : string;
  M,N        : integer;
  FirstSpace : boolean;
begin
  writeln;
  write('Enter string :  ');
  readln(OrigStr);
  ResultStr := '';
  M :=1;
  FirstSpace := FALSE;
  for N := 1 to length(OrigStr) do
  begin
    if (OrigStr[N] <> SPACE) then
    begin
      ResultStr[M] := OrigStr[N];
      inc(M);
      inc(ResultStr[0]);
      FirstSpace := TRUE;
    end
    else
    begin
      if (FirstSpace) then
      begin
        ResultStr[M] := SPACE;
        inc(M);
        inc(ResultStr[0]);
        FirstSpace := FALSE;
      end;
    end; {if}
  end; {for}
  if (ResultStr[M-1] = SPACE) then dec(ResultStr[0]);
  writeln('Result string = ',ResultStr);
  readln;
end.