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

Ex Input:
ChKUlYUTQQBjZMZkgEed, lmQQBjZMZkgdEf

Ex Output:
QQBjZMZkg


Ex Input:
uqazNuZhdJhw, KbnrzNuZhBdp

Ex Output:
zNuZh


Ex Input:
VHHnuqGgzoZdbVgHSpApBiCAA, VQwJvoZdbVgHSpftg

Ex Output:

oZdbVgHSp