instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
yhhzISsXKEbA, KlPrazISsXKzmrVBG
answer:
zISsXK


question:
zfUPUDeKbCMQa, BkAJFJUDeKbCMZmkFu
answer:
UDeKbCM


question:
hnwKgxBYigwWNRuVqgoEfQhw, kxxmjYkNkigwWNRuVqLFpH
answer:

igwWNRuVq