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

[EX Q]: FCKbAgSVgj, wAEAWbAgSVSVwD
[EX A]: bAgSV

[EX Q]: spGRUmIYuGl, qkqRUmItqU
[EX A]: RUmI

[EX Q]: GaJozvDHULRlhNJIcKZSpuV, FJFqULRlhNJIcgE
[EX A]:
ULRlhNJIc

