It should tell you somewhere on the bottle, if not ring them up and ask. There are lots of different strengths out there I did struggle to find one that you didn't need to take multiple pills for, I think I did find a 50 in the end as I remember taking two pills.
It may be worth a try with irregular ovulation, that is why I tried it. It does work for a lot of people.
Other things I've tried are agnus castus (1000mg through my whole cycle, some people stop after ovulation but again I could find no scientific study to back this up only forum gossip) I tried this for 6 months and it did regulate my cycle to start with and then it went nuts again and so I stopped.
I also tried Black cohosh, I think this one was 1200mg on cycle days 2-12, I did get strong ovulation on this. I did it for three cycles and stopped because I went on to clomid.
I wouldn't try any of these if you have a regular cycle but when your cycles are a bit nuts it is tempting to see if any of these will help it, which is why I tried them while I was waiting for clomid. I figured I had nothing to lose.