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

Q: OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq

A: ERnjubLF
****
Q: GHdeqnuYnQ, zzQeqnutAZ

A: eqnu
****
Q: FAmYMwCuvqZE, UMbSYMwCuvDo

A:
YMwCuv
****