{--------------------------------------------------------------------------
DATA ENCODING:

The magic values are $EA, $EB, $EC, $ED.

$EA + char + byte =  insert [byte] [char]:s to output.

$EB + char + lobyte + hibyte = insert [address of( lobyte + hibyte )]
                               [char]:s to output ( if # of chars is
                               greater than 255 )

$EC = eof

$ED + [ $EA, $EB, $EC, $ED ] = insert command char to output.

--------------------------------------------------------------------------}

program rllencode;

var
  infile: file of byte;
  outfile: file of byte;
  b, b1 : byte;
  bytecnt: LongInt;
  f: Text;

function HowManyLikeBytesInARow( bByte: Byte ): LongInt;
var
  fp : longint;
  b : Byte;
  counter : longint;
begin
  counter := 0;
  b := bByte;
  fp := filesize( infile );
  while ( b = bByte ) and ( FileSize( infile ) <> FilePos( infile ) ) do
  begin
    fp := FilePos( infile );
    Read( infile, b );
    inc( counter );
  end;
{  if ( b <> bByte ) then}
  Seek( infile, fp );
  if counter < 1 then
    counter := 1;
  if counter > 2 then
    writeln( f, counter );
  HowManyLikeBytesInARow := counter;
end;

begin
  if ParamCount <> 2 then
    halt;
  Assign( infile, ParamStr( 1 ) );
  Assign( outfile, ParamStr( 2 ) );
  Assign( f, 'len2.txt' );
  reset( infile );
  rewrite( outfile );
  rewrite( f );
  while ( filepos( infile ) <> filesize( infile ) ) do
  begin
    Read( infile, b );
    bytecnt := HowManyLikeBytesInARow( b );
    if ( bytecnt = 1 ) then
    begin
      if ( b = $ea ) or ( b = $eb ) or ( b = $ec ) or ( b = $ed ) then
      begin
        b1 := $ed;
        write( outfile, b1 );
        write( outfile, b );
      end
      else
      begin
        Write( outfile, b );
      end;
    end;
    if bytecnt = 2 then
    begin
      if ( ( b <> $ea ) and ( b <> $eb )
           and ( b <> $ec ) and ( b <> $ed ) ) then
      begin
        write( outfile, b );
        write( outfile, b );
      end;
      if ( ( b = $ea ) or ( b = $eb )
           or ( b = $ec ) or ( b = $ed ) ) then
      begin
        b1 := $ea;
        write( outfile, b1 );
        write( outfile, b );
        b1 := 2;
        write( outfile, b1 );
      end
    end;
    if bytecnt > 2 then
    begin
      if ( bytecnt < 256 ) then
      begin
        b1 := $ea;
        write( outfile, b1 );
        write( outfile, b );
        b1 := bytecnt;
        write( outfile, b1 );
      end
      else
      begin
        b1 := $eb;
        write( outfile, b1 );
        write( outfile, b );
        b1 := bytecnt mod 256;
        write( outfile, b1 );
        b1 := Trunc( bytecnt / 256);
        write( outfile, b1 );
      end;
    end;
  end; {while}
  close( infile );
  b1 := $ec;
  write( outfile, b1 );
  close( outfile );
  close( f );
end.