Multiple Separate If Forumlas In One Cell

I have multiple collumns with monetary value that are intended to automatically be deducted once the previous collumn is depelted.

I need to also have the values stop at 0 and not go into the negatives.

Here is what I have now

=IF(K12<=0,SUM(I11*5%)+I11-M12, IF(AND(I12<=0,K12<=0 )=TRUE, 0,SUM(I11*5%)+I11-M12))

Basically I have collumn 1 and 2

collumn 1 collumn 2

100,000 50,000

I need to have collumn 1 start to be deducted once collumn 2 reaches zero. I also need both collumns to stop at zero and not go negative.