matching sets and ids

Hi,

I have two files :
File A contains the following :
((((9,(6,8)),((4,((3,2),1)),5)),(12,11)),(13,(7,10)));

File B contains the follwoing:
1 A
2 B
3 C
4 D
5 E
6 F
7 G
8 H
9 I
10 J
11 K
12 L
13 M

Based on the file B, I want to modify the file A such that all numerics in
file A get changed to the alphabets in column 2 of file B (by mapping column
1 of file B to file A) such that file A is effectvly modified to :
((((I,(F,H)),((D,((C,B),A),E)),(L,K)),(M,(G,J)));

Is there a way of doing it in perl ?

Thanks