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

Ex Input:
aIZIsqL, wxSZIsEnO

Ex Output:
ZIs


Ex Input:
jeQzwP, kSQzxq

Ex Output:
Qz


Ex Input:
YzdQhrTzJnVsRgWdSIgnsqQ, hhETzJnVsRgWwVRxjBz

Ex Output:

TzJnVsRgW