David arranges a total of $100$ books on $4$ shelves.
There are $2$ more books on the $2$nd shelf than the $1$st shelf.
There are $3$ more books on the $3$rd shelf than the $2$nd shelf.
There are $4$ more books on the $4$th shelf than the $3$rd shelf.

How many books are on the $3$rd shelf?