Twenty Eleven: Delete Search Box, Reclaim Empty Space on menu bar

I have a simple site/blog which uses twenty eleven theme. It has a banner as the header image, a black menu bar with 6 columns, each column with a name and links to one of six different pages, and a search bar on the right in the seventh column. I wanted to delete the search box so I looked here:

https://www.ads-software.com/support/topic/remove-search-box-twenty-eleven/page/2?replies=13#

And edited header.php. Now the search box is gone. However, there is empty space where the search box used to be in the seventh column. If I try to add a seventh page, it makes the menu bar two rows instead of one.

Now that my search box is gone, how can I reclaim the space previously occupied by it on upper right corner to allow me to add a seventh page/column to the menu bar?