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

Ex Input:
XHqQIPw, brqQIkAt

Ex Output:
qQI


Ex Input:
JjEQVKijeyEQ, dwSVKijeywCTvb

Ex Output:
VKijey


Ex Input:
fDluAMdiVGK, FgXuAMdalIF

Ex Output:

uAMd