What's the best amount of cranberry pills to take to prevent an urinary tract infection?

The bottle of cranberry pills I got at the pharmacy (on the shelf, didn't need a prescription) says it's for PREVENTION of RECURRENT UTIs. I've only had one UTI but it was such a painful experience that I don't want to live it again, and sometimes I feel like I'm getting one so I'd just chug warm water mixed with baking soda. Anyways on the bottle of my cranberry pills it says to take to pills twice daily (so four altogether) for a minimum of four weeks for it to be beneficial. Is it okay if I just take 2 a day since I don't really have RECURRING ones, just am wanting to be cautious?