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

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


[Q]: SFQHJlK, dHfQHJoUC
[A]: QHJ


[Q]: amFfgPfCW, PzxfgPco
[A]:
fgP