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

Q: AxAmDG, LTAmEV

A: Am
****
Q: HEVqGddewrNqiZ, iyvlddewrNXr

A: ddewrN
****
Q: byCzNDuHXjAzyUALmht, BVpxsDuHXjAzwcu

A:
DuHXjAz
****