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

Ex Input:
TTagIJmzrOTdnKr, UONmtdHJmzrOTduWo

Ex Output:
JmzrOTd


Ex Input:
egYXVtCPvWxP, VMOolyVtCPvWjIx

Ex Output:
VtCPvW


Ex Input:
ydvMqmH, cBvMqkwt

Ex Output:

vMq