instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML
answer:
chtNymcsw


question:
XqyPjqNZDEK, EfwPjqNgjIP
answer:
PjqN


question:
MOIIGKiGluR, eRpgQGKiGlykMGo
answer:

GKiGl