instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
YcgVJVACcQE, JsJVACcSz
answer:
JVACc


question:
HqaOvLaZbs, RifOvLaZkh
answer:
OvLaZ


question:
XCupldlSqbJG, shExdlSqbxWd
answer:

dlSqb