instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
XZslQqrShfCXRXyHrFVq, BtOQgQqrShfCXRRCRbMvXPM
answer:
QqrShfCXR


question:
ocjsZZfSBBopDtgWUT, rWmgzsZZfSBBoGWQ
answer:
sZZfSBBo


question:
xlICdckGg, ZGICdcHLSK
answer:

ICdc