use strict;
my %calls;
while (<>) {
  my $line = $_;
  my ($num, $source, $dest, $type) = split (/\s+/,$line,5);
  my $key;
  if ($type eq "GetReply") {
     $key = $dest . ":" . $source;
  } else {
     $key = $source . ":" . $dest;
  }
  push @{$calls{$key}}, $line;
}

foreach my $k (sort keys %calls) {
   print join('', @{$calls{$k}}),"\n\n";
}