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

Ex Input:
apGMPThLTCw, LvMPThYW

Ex Output:
MPTh


Ex Input:
yjoJzBGdwfOhsceoOpoap, uSLMdBGdwfOhsIQHBijd

Ex Output:
BGdwfOhs


Ex Input:
zWYCsHNXXBqWtcrdiACebe, GmxkSYCsHNXXBqWLFxlIB

Ex Output:

YCsHNXXBqW