Finding height between high points
 

Hi,

I have a column of numbers, say:
1
2
3
4
3
2
3
4
5
4
3
7
5

I am looking for a formula that will calculate the height above the previous
low point.

1 . (Low point)
2 1
3 2
4 3
3 2
2 1 (New low point)
3 1
4 2
5 3
4 2
3 0 (New low point)
7 4
5 2

I can do it in three steps, by first locating all the Low points (Column B),
them by calculating the height of the last low point (Column C), then by
calculating the difference. This is taking up too much real estate in my
spreadsheet and I was hoping to combing this into one formula.

Any assistance will be appreciated.

Sean