After he started the religion , he changed his name to BÃ b. People who believe in the BÃ b are called BÃ bÃ s , and they believe that the BÃ b was a prophet . This time , the BÃ b and his companion were killed . In the BÃ bÃ â `` BahÃ ' Ã tradition , the failure of the first firing squad to kill the BÃ b is believed to have been a miracle .