How can I extract text between 2 first dash line?

Hello everybody,
Here is my text pattern, how can I get the text between 2 first dash line?

534-106-5301121142-DOCUMENT.pdf
534-50-5301121138-DOCUMENT.pdf
534-0-5301081001-DOCUMENT.pdf
For example, I want to get 106 from line 1, 50 from line 2, and 0 from line 3.

Any idea? I have tried to use substring function but it doesn't works well. (inflexible when the number more than 1 character)
Thanks in advanced!
Novox


534-6-5301121142-DOCUMENT.pdf 12 ?.?. 2553 11:42 ?. Go to the complete details ...