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

Ex Input:
YCAyruPTTHWhCYaiXfIl, OETdzqAyruPTTHWgS

Ex Output:
AyruPTTHW


Ex Input:
rduIwWNGM, AJqYIwWNaCap

Ex Output:
IwWN


Ex Input:
gzTNtlkGLQSUSk, MKTNtlkGLpNtSx

Ex Output:

TNtlkGL