Add number from a cell that contains a specific character
 

I want to look in a range of cells (a1:d1) add the left number for all that
meet the criteria (a or A). I have tried variations but have yet to get it
to add.

A B C D
1 2 C 2 a 2 S 2 A
2 1 c 2 A 1 LS 1 C

I need to leave the number and character in the same column with the space
between them.