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

[Q]: GFhJafTV, waHhJaji
[A]: hJa


[Q]: ykDpbd, YFDpmO
[A]: Dp


[Q]: LQHnBeSfJvuwxsTygsVpH, GToLtdCGBeSfJvuwxOBSPvCKN
[A]:
BeSfJvuwx