instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
fCGEhfHvcRouHzNw, gtjBkhfHvcRouHee
answer:
hfHvcRouH


question:
CUlMsvov, iflMsSRp
answer:
lMs


question:
lAIRpCHdyWBY, eFapCHdyWLW
answer:

pCHdyW