instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
yJRITYgVTSNsPjG, NSIdKYgVTSNmj
answer:
YgVTSN


question:
WFAPUCgVYbmZiFlacUzyv, xQFiekrgPUCgVYbmZUEtl
answer:
PUCgVYbmZ


question:
iJsriWPUR, fZxvriWPTBci
answer:

riWP