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

Ex Input:
sRTQgRgRUjEooapKdR, vzsBgRUjEooLBkYeH

Ex Output:
gRUjEoo


Ex Input:
kWTQrtCaoTbXIiXDphMG, pLhxkfeDoTbXIiXDpCCzTYyZv

Ex Output:
oTbXIiXDp


Ex Input:
VByrCcgcxCfPGDFqIWGloQZTMQf, OqfPGDFqIWGlalTCCkKkMf

Ex Output:

fPGDFqIWGl