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

Q: bUHPpvVtFQNSpUdg, zggEFoKBHPpvVtFQNHXsc

A: HPpvVtFQN
****
Q: uqDaPS, XyDaMZ

A: Da
****
Q: jinzsW, SMnzaW

A:
nz
****