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

Q: sEYtoQlG, XIstoQQPw

A: toQ
****
Q: YKpdeJQhzyYiPoODACUu, mjmnIlCehzyYiPoOzZ

A: hzyYiPoO
****
Q: lXFmkjJJeTYJ, yxFmkjJGpRS

A:
FmkjJ
****