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

[EX Q]: eFUexDIFlaPDUwrOb, mTvkKGUxDIFlaPDUwxGVpnIwbi
[EX A]: xDIFlaPDUw

[EX Q]: OBzHWjmkcgVGPyv, gCHWjmkcgVMq
[EX A]: HWjmkcgV

[EX Q]: VvenPdlcKfzS, bUYoPdlcKnXZ
[EX A]:
PdlcK