instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sOSXbnluNuvwMETKda, JzXbnluNuvyeVHO
answer:
XbnluNuv


question:
sUdaWtsiRgqAYHykrHwjyDvZgD, MJdFXYiRgqAYHykrakSGHMr
answer:
iRgqAYHykr


question:
haOsaSQcyodWhqQaC, BKLEUQcyodWhvVkmxBz
answer:

QcyodWh