instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
fREVIdeTcakgFnwDWTVev, IbtXImseeTcakgFnwDYsKBAlux
answer:
eTcakgFnwD


question:
gwVLygvd, VOQLyglfo
answer:
Lyg


question:
hSWiqxolah, cHiqxoMx
answer:

iqxo