In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

[EX Q]: RAmKlEAUfWcgF, ZlWfEAUfWvVRa
[EX A]: EAUfW

[EX Q]: ZyrpGdXvvtrKQIxU, CLNGdXvvtrKQDpicfqLdt
[EX A]: GdXvvtrKQ

[EX Q]: MCHGztUTblefPPddFZ, QBdRvkSzZUTblefPPddDWALRGZp
[EX A]:
UTblefPPdd