instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
ZGkBNEDRAwURXnxBIOJkzTvg, HMAwURXnxBMfGbPOBf
answer:
AwURXnxB


question:
PIcbiJj, hedcbiZHF
answer:
cbi


question:
igGDreTw, wjDrewn
answer:

Dre