instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
ezVsFayUPcrte, lfsFayUMPTqx
answer:
sFayU


question:
oDdulHNcCdgbRGxiBTxM, kDcCdgbRGnsJlvas
answer:
cCdgbRG


question:
uEjFuDHaeiBWvseCFF, BKiQFuDHaeiBWvjJfuZrv
answer:

FuDHaeiBWv