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

Q: faHRBWyXsYzYmHQyy, aHTyXsYzYeXBFV

A: yXsYzY
****
Q: HEVqGddewrNqiZ, iyvlddewrNXr

A: ddewrN
****
Q: kMlnwstI, GjlnwWcU

A:
lnw
****