instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
fdinRdwwlntwqzYGhV, ZefonRdwwlntoWQbh
answer:
nRdwwlnt


question:
wnIFoRQvMMKMAqpCQYncuWUTJs, bPMUKKxYRxQvMMKMAqpCmzAPPMD
answer:
QvMMKMAqpC


question:
XtGosPNHwtw, tYLsPNHwLmDSz
answer:

sPNHw