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

Ex Input:
zzEhnt, sYEhtc

Ex Output:
Eh


Ex Input:
dReySjyqecU, loSjyqiRl

Ex Output:
Sjyq


Ex Input:
rXnakMHcCkCBfmdiE, osgemcCkCBfmdssuSiYw

Ex Output:

cCkCBfmd