I understand what FSB & FBS are (Front, Back, Split FBS) (Front Split Back) and taking the current Pick 3 winning drawing and then taking the previous 3 drawings to see if any digit(s) are in the winning pick 3 set. For example, Pennsylvania pick 3 evening drawing from 3/30/2023 was 703 straight / 037 box. The previous 3 drawings were 005, 369, 257 box form. 050, 639, 752 straight.
What detemines the "F"? What determines the "S"? What determines the "B"
Thanks