Custom Indicator: max difference, in absolute value, between two SMA's for a fixed number of periods

Hi, Thanks for taking a look at this simple Custom Indicator job. I know how to do it on R, but don't have the MQL skills.  The excel file of the screenshot is attached.

Description:

I need an indicator that evaluates the maximum difference, in absolute value,  between two simple moving averages for a fixed number of periods.

custom indicator will be named:   

"MA delta max"

Indicator format:  line in separate window

3 configurable input variables:

• MA1    example 200 for SMA200
• MA2    example   50 for SMA50
• p         example  150 to look 150 periods back   (ex 150 days if  chart is Daily)

* both are Simple Moving Averages, at close, no shift

formula possible syntax (no specific programming language): 

Max( Abs( MA1[(now-p) : (now)]   - MA50[(now-p) : (now)]))

It should match the picture here below, where indicator fetches the maximum value in p range:

* notice that a p value of 0 (as in current value)  is always included.  So p =3 actually reads 4 data points.