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

[EX Q]: NmtypJ, tQtyZD
[EX A]: ty

[EX Q]: VTwtMVKmrRvL, WLoVtWtMVKmrDCke
[EX A]: tMVKmr

[EX Q]: dfPxcpjAbnAhP, XkEFBxcpjAZolJ
[EX A]:
xcpjA