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

Q: rszjOPpbXm, pnBujOPpWHz

A: jOPp
****
Q: yiKkIxbKvNk, znaIxbKggg

A: IxbK
****
Q: gzPLHQEgOLUL, ixHQEgegR

A:
HQEg
****