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

Q: nYoRQU, gQoRZQ

A: oR
****
Q: mJoHBJehHtkFS, ZMrDxHBJehHtxS

A: HBJehHt
****
Q: xHdOwYSMpV, xddOwYSMrozURC

A:
dOwYSM
****