This was taken and improved slightly from Question that has since been deleted
For those who can see deleted posts, it was taken from here: https://
You can do this just by adding the results of two matches together. One match for the names plus one match for the letter equals the total row.
=INDEX(A:D,MATCH(G5,A3:A5,0)+MATCH(G3,A:A,0),MATCH(G4,1:1,0))
In other words: Index(All of the Data, Match(Name, In name column, exact) + Match(Letter, In letter column, exact), Match(Column name, in Column row, exact)
Screen capture of working sheet