Oh well I'm trying it from several hours It's  4am here now and i can't do it anymore..
I did some mistake, probably you guys can do it properly.

OP said A = 10  BabyA a =36

Now take a look at your keyboard.

QWERTYUIOP  Q=0 W=1 E=2 R=3 T=4 Y=5 U=6 I=7 O=8 P=9
ASDFGHJKL A=10 s=11 D=12 F13 G14 H15 J16 K17 L18
ZXCVBNM Z19 X20 C21 V22 B23 N24 M25

Now if we will carry digits to lower case
qwertyuiop q=26 w27 e28 r29 t30 y31 u32 i33 o34 p35
asdfghjkl a=36 s37 d38 f39 g40 h41 j42 k43 l44
zxcvbnm z45 x46 c47 v48 b49 n50 m51