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

Q: IGHhMfqLeBpnullsPInfBH, LTDBpnullsPIBynwCrCQ

A: BpnullsPI
****
Q: txJhzNeBj, qLJhzNesV

A: JhzNe
****
Q: QurRKzYEKqcvxzM, RYmHSrrRKzYEKqoKaF

A:
rRKzYEKq
****