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

Q: bOvlVNWf, iivlVzWt

A: vlV
****
Q: sEYtoQlG, XIstoQQPw

A: toQ
****
Q: FDYVjnEoRLU, ugdVjnEoJtVPz

A:
VjnEo
****