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

wbFDXJQDQxQJzudOUlR, QEbsIDXJQDQxQsSYIutwU
DXJQDQxQ

UovaYpHjYSQzrfsxRfvIZE, pUOFxIKOGQzrfsxRfvIjrza
QzrfsxRfvI

zmQrzTtjyVNgUEHeGUsApB, YBOIQrzTtjyVNgjdY

QrzTtjyVNg

