instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
OBzHWjmkcgVGPyv, gCHWjmkcgVMq
answer:
HWjmkcgV


question:
eeoJEtGHPDvHck, ezPGHPDvHSf
answer:
GHPDvH


question:
FWhntzDTwWdIfcC, grntzDTwWdsHQw
answer:

ntzDTwWd