MARY J. BLIGE isn't bitter she lost hit track UMBRELLA to Rihanna - insisting it was too mainstream for her. The R+B diva tried to record to the song, but it was handed to Rihanna instead. Now Blige claims she was happy to let the Barbadan beauty take the tune to the top of the charts around the globe - so she could concentrate on creating her own sound. She says, "I'm not going to chase what (mainstream) fans like. It might work for a Mariah. It might work for a Beyonce. But Mary J. Blige is looked at as some sort of organic thing."