instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
xeKSiBafhOWBbYwlGaQ, GUfIsKgafhOWBbYiFWnptAt
answer:
afhOWBbY


question:
cZSEmdgP, YsSEmEIM
answer:
SEm


question:
TvrSFrvDPLXBZ, AqSFrvDPlH
answer:

SFrvDP