instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
yKtQOhYvrJVH, HQsTQOhYvPP
answer:
QOhYv


question:
AxAmDG, LTAmEV
answer:
Am


question:
XCcbacwSVUMOwCCNs, LrDWbacwSVUZmkA
answer:

bacwSVU