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

[EX Q]: LJJvLTK, jpFJvLqh
[EX A]: JvL

[EX Q]: ilgSzrcUKLTNLJbMKMKSt, hFXIuUKLTNLJbMKWxSCkDjY
[EX A]: UKLTNLJbMK

[EX Q]: dWYjSuiRRgjJAKPwQAriJ, XSEiRRgjJAKOvBMqf
[EX A]:
iRRgjJAK