#!/usr/bin/perl

@lines = ();
while (<>) {
  push @lines, $_;
}

sub count {
  my $pat = shift;
  my $count = 0;
  foreach (@lines) {
      while (/[ ()]$pat[ ()]/g) { $count++; }
  }
  return $count;
}



$last_count = -1;
while (1) {
@out = ();
$count = 0;

LINE: foreach (@lines) {
  $line = $_;

  next LINE
    if (/^\(= (XX\d+) .*\)$/ && count($1) == 1);
  
  next LINE
    if (/^\(= .* (XX\d+)\)$/ && count($1) == 1);

  next LINE
    if (/^\(NOT \(= (XX\d+) .*\)\)$/ && count($1) == 1);
  
  next LINE
    if (/^\(NOT \(= .* (XX\d+)\)\)$/ && count($1) == 1);

  push @out, $line;
  $count++;
}

last if ($count == $last_count);
$last_count = $count;
@lines = @out;
}

foreach (@out) {
  print;
}