Secret of success of a CA

A C.A. in a big firm had a very strange habit...Every morning he used 2 open his drawer, luk at a paper n den lock d drawer again...D trainees were very curious n thought dat he has d secret of his success in tat drawer..!So 1 day wen d CA was out, d trainees decided 2 break d lock.Wen dey broke d lock n took out d paper, itwas written on d paper..."Left is debit, right is credit"😆😆