instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
AkYuNemHGBEDF, uluNemHGAycbWX
answer:
uNemHG


question:
lPhVhAQZWJDrvzcEaGEwKgZAuJI, qIJDrvzcEaGDRCRrB
answer:
JDrvzcEaG


question:
PGuFUYTpIsP, wBNbFUYTfNiP
answer:

FUYT