Interesting Function

You are given two integers $$$l$$$ and $$$r$$$, where $$$l < r$$$. We will add $$$1$$$ to $$$l$$$ until the result is equal to $$$r$$$. Thus, there will be exactly $$$r-l$$$ additions performed. For each such addition, let's look at the number of digits that will be changed after it.

For example:

• if $$$l=909$$$, then adding one will result in $$$910$$$ and $$$2$$$ digits will be changed;
• if you add one to $$$l=9$$$, the result will be $$$10$$$ and $$$2$$$ digits will also be changed;
• if you add one to $$$l=489999$$$, the result will be $$$490000$$$ and $$$5$$$ digits will be changed.

Changed digits always form a suffix of the result written in the decimal system.

Output the total number of changed digits, if you want to get $$$r$$$ from $$$l$$$, adding $$$1$$$ each time.