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

Q: mQvintdwLUpClREgxv, rYnoXBtdwLUpClRwxsqX

A: tdwLUpClR
****
Q: BICndZkjoSidWivWATvtqsS, FzVWjoSidWivFaQhkRT

A: joSidWiv
****
Q: EGOONfTiK, YzAHONfThn

A:
ONfT
****