How to count the row's values

Question

Hi!

 

I have this simple table generated in a datagrid, a label where the default amount is 1.029. What I need to learn?

For each row there is a specific operation. For example, the official fees amount is 1.029. Then Fred doesnt paid for July and Agust. Then its should pay two months (1.029 x 2 = 2.058 ). Brune should pay only one month: Agust (1.029). But Shandi is three months: June, July, August (1.029 x 3 = 3.087).

How can I in a simple way count the month(s) is (or are) on each row as we can see on this table?

 

Name                Month               Amount -------------|-------------------------|--------------  Fred              July, Agust                1.029 -------------|-------------------------|--------------  Brune           Agust                         1.029 -------------|-------------------------|--------------    Shandi         June, July, Agust      1.029 -------------|-------------------------|--------------   In another way, any month inserted in each row is considered as "1". If we add another month on the same row is "1" + "1" = 2.