use Time::Local;
...
	my $ref = shift;
	my $date1 = shift @$ref;
	my $time1 = shift @$ref;
	print "-1\n" and exit unless $date1 =~ /(\d\d)(\d\d)(\d\d)/;
	my @date2 = ($1,$2,$3);
	print "-1\n" and exit unless $time1 =~ /(\d\d):(\d\d)/;
	my @time2 = ($1,$2);
	my $t;
	eval {$t = timegm(0,$time2[1],$time2[0],$date2[1],$date2[0]-1,$date2[2]+100)};
	print "-1\n" and exit if $@;
...