var
  f: file of char;
  count, k: integer;
  c: char;

procedure wrFile;
var
  c: char;
begin
  reset(f);
  while not eof(f) do
  begin
    read(f, c);
    write(c);
  end;
  close(f);
  writeln;
end;

begin
  rewrite(f, 'C:\Users\Дом\Desktop\For Time\file.ch');
  writeln('Кол-во символов:');
  readln(count);
  if count = 0 then
  begin
    writeln('В файле нет символов.');
    halt;
  end;
  for var i := 1 to count do
    write(f, chr(random(33, 120)));
  close(f);
  wrFile;

  reset(f);
  k := 0;
  for var i := 0 to Filesize(f) - 1 do
  begin
    Seek(f, i);
    if not odd(i) Then
    begin
      Read(f, c);
      Seek(f, k);
      Write(f, c);
      Inc(k);
    end;
  end;
  Seek(f, k);
  Truncate(f);
  close(f);
  wrFile;
end.