=head1 1
Contents of section 1
=head2 1.1
Contents of section 1.1
=head3 1.1.1
=head4 1.1.1.1
=head1 2
Contents of section 2
=head2 2.1
Contents of section 2.1
=head4 2.1.1
Contents of section 2.1.1
=head3 2.2
Contents of section 2.2
=head1 3
Contents of section 3