In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
--------
Question: SIIPePlrkftKkzfgdjg, JqNnXHrkftKkzOMUwmc

Answer: rkftKkz


Question: AxAmDG, LTAmEV

Answer: Am


Question: fqzHvp, HyzHfo

Answer:
zH