instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
QlJnxO, BLJnCQ
answer:
Jn


question:
rRmkmETbjzCzZZxihrVdefxfcenJ, ogQtzAgWjKCzZZxihrVdRswMCmngp
answer:
CzZZxihrVd


question:
NqPHWyYS, PhPHWIaA
answer:

PHW


