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

Q: YKpdeJQhzyYiPoODACUu, mjmnIlCehzyYiPoOzZ

A: hzyYiPoO
****
Q: OyXwTWbLByC, yODnTWbLWYzc

A: TWbL
****
Q: uWWttz, dAWtfD

A:
Wt
****