Hello everyone, I am looking for a formula that can look up several different
letter combinations and calculate the values in the corresponding cells. An
example:

There is a host of letters such as "AAB", "BMN", etc. in multiple cells at
the coordinates of 13 columns and multiple rows. Each of those cells has an
adjacent cell that contains a value.

I need the formula to sum the values of the cells that match each of those
particular letter combinations.

Appreciate your help