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

Ex Input:
SJIkEibGrqcrOBgGjYjJc, EervOGrqcrOBgGJZyx

Ex Output:
GrqcrOBgG


Ex Input:
rduIwWNGM, AJqYIwWNaCap

Ex Output:
IwWN


Ex Input:
BwICbvJv, CiCbvPF

Ex Output:

Cbv