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

Q: BmxgSFWBlVX, kGgKrgSFWBlGunFcZ

A: gSFWBl
****
Q: rPPfxUdowLLdvwRtY, PuHovApkfxUdowLLBOhq

A: fxUdowLL
****
Q: tElRRSkADbXrIrkBRqL, VRLRSkADbXrIRjCuwanuE

A:
RSkADbXrI
****