Counting consecutive cells that have value, IF there are 3 consecutive cells, just once

Hello,

my first post here, sofar i have always been able to find a solution reading someone elses problems. here is mine:

I have rows with client numbers and columns with months in 1 year. Some clients have payments in some months. I need to:

- find in which month starts the occurence of 3 consecutive cells with payments (so > 0)
- sum them up (only those 3)
- ignore any other occurence of 3 consecutive cells that fulfill the mentioned conditions
- if there are no occurences, mark, put a string or number into the resulting cell (like "no data")
- if the 1st payment occurs in november or december (so there is not enough months to meet the 3-cell condition), put a string "forecast", or something numerical


Let me attach an example table with dummy data and what should resulting cells contain.

Book1.xlsx


Thanks a lot for your help

For Client no.1 Mar is 0 and april is 5463 then what is your result for jan

i am not asking about original data
for suppose if For Client no.1 Mar is 0 and april is 5463 then what is your result for jan

Then
=IFERROR(IF(SUM(INDEX(B2:M2,MATCH(N2,B$1:M$1,0)):INDEX(B2:M2,MATCH(N2,B$1:M$1,0)+2))=0,"No Data",SUM(INDEX(B2:M2,MATCH(N2,B$1:M$1,0)):INDEX(B2:M2,MATCH(N2,B$1:M$1,0)+2))),"Forecast")
Try this