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

Ex Input:
bdCOjNchdKtvWzOI, FwejNchdKhEd

Ex Output:
jNchdK


Ex Input:
cfvqbAUpWEmhCSFaUvGrYVNGeUiRP, hAxWMEmhCSFaUvGLBLmdTxhy

Ex Output:
EmhCSFaUvG


Ex Input:
kNUQAHuN, QfpQAHCu

Ex Output:

QAH