instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
KfjqnJLciTXqkJK, yqfRcfqnJLcisSB
answer:
qnJLci


question:
OBzHWjmkcgVGPyv, gCHWjmkcgVMq
answer:
HWjmkcgV


question:
AyGpLhrHy, owpLhrlIR
answer:

pLhr