;255
function f($)
  dim $h,$c,$o,$t,$a
  $f=ubound($)
  do
    $h=$c+1
    do
      $a=$[$c]+$[$h]
      if len($a)=2*len(join($,""))/($f+1)
        $o=$o + " "+$a+" "+$[$h]+$[$c]
      endif
      $h=$h+1  
    until $h>$f
    $c=$c+1
  until $c=$f
  $o=trim($o)
  for each $ in split($o)
    $h=ubound(split($o,$))
    if $h>$t
      $t=$h
      $f=$
    endif
  next
endfunction