instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
HKCoXQsLRtowYJ, PGRzNUQsLRtoLcqkn
answer:
QsLRto


question:
SeXNqRAbKdLuWXgb, npsIWRAbKdLuUWSbvuS
answer:
RAbKdLu


question:
cpRDMhvdrwUYXuWcEhspkqZeC, gjhvdrwUYXuWpYrV
answer:

hvdrwUYXuW