Sure, DCC, happy to help.
A/S = "authorized shares" or the total number of shares that can be issued at any time. That doesn't mean they are outstanding, only "allowed" to be issued by the board of directors.
O/S = "outstanding shares" or the total number of shares issued and in circulation.
FYI, O/S multiplied by the price per share (PPS) equals the Market Capital, or the dollar value of the company.
GLTY, and happy trading.