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

Ex Input:
TnbLNKnNSs, NhDLNKnNRd

Ex Output:
LNKnN


Ex Input:
RwduMBkDazrwZP, UPzcwtWMBkDazrAw

Ex Output:
MBkDazr


Ex Input:
GRKVHsWbdMAp, vYKHsWbcLCV

Ex Output:

HsWb