instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
nWTnWqkLqYTBxT, cSTnWqkLqYwXmxRF
answer:
TnWqkLqY


question:
gfXPLNzsyfEotmHL, oJeXPLNzsyJuXP
answer:
XPLNzsy


question:
LwPEpLGgY, ONsEpLfiD
answer:

EpL