use strict;
my %locks;

while (chomp(my $line = <STDIN>)) {
	next unless ($line =~ /Mutex(.*)::(.*)/);
	my ($mutex,$action) = ($1,$2);

	if ($action eq 'locking') {
		if ($locks{$mutex}) {
			printf ("Mutex %s already locked on line %d, locked again on line %d\n",
				$mutex, $locks{$mutex}, $.);
		} else {
			$locks{$mutex} = $.;
		}
	} elsif ($action eq 'unlocked') {
		if ($locks{$mutex}) {
			delete $locks{$mutex};
		} else {
			printf ("Mutex %s unlocked on line %d, but wasn't locked.\n",
				$mutex, $.);
		}
	}
}

foreach my $mutex (keys %locks) {
	printf ("Mutex %s locked on line %d, but wasn't unlocked\n",
		$mutex, $locks{$mutex});
}