instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
egYXVtCPvWxP, VMOolyVtCPvWjIx
answer:
VtCPvW


question:
SeXNqRAbKdLuWXgb, npsIWRAbKdLuUWSbvuS
answer:
RAbKdLu


question:
QtgyhMHl, LHIGgyhMrV
answer:

gyhM