Running sum based on outflow/inflow cash

[#1]

My pivot table looks like this: http://i49.tinypic.com/ofsxs7.gif

It's sorted by date DESC (First dimension, "Effective Chec...").

I'm trying to get a running sum to get Amount of cash on hand in the "Amt" column.  You can see the Inflow and Outflow columns to its left...

I tried this, didn't work: =RangeSum(Above(TOTAL Sum(Amount),0,RowNo()))