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

[EX Q]: CkZOSZevST, bbZOSZIg
[EX A]: ZOSZ

[EX Q]: zzEhnt, sYEhtc
[EX A]: Eh

[EX Q]: HjOfyzifido, jvFfyzifWt
[EX A]:
fyzif

