open(IN, "<sort.in") || die "\nFailed to open infile $?\n";
open(OUT,">sort.out");
my @array;
while(<IN>) {
  if (/<SEP>/) {
    print OUT join '',sort {$a <=> $b} @array;
    print OUT "<SEP>\n";
    @array=();
  } else {
    @array = (@array,$_);
  }
}
print OUT join '',sort {$a <=> $b} @array;
close OUT;
close IN;