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

Q: XeQwOS, OuQwNR

A: Qw
****
Q: BICndZkjoSidWivWATvtqsS, FzVWjoSidWivFaQhkRT

A: joSidWiv
****
Q: BWMoNWrXqapMIM, erWrXqapzVLVkK

A:
WrXqap
****