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

Ex Input:
TvNVpHLPYjBCeUpyxlzFZ, tgKdPKVYjBCeUpyPK

Ex Output:
YjBCeUpy


Ex Input:
EJZYVxgFxPoOSDlLfK, uTLTIETHZYVxgFxPoPwr

Ex Output:
ZYVxgFxPo


Ex Input:
LRtxyP, ArtxIz

Ex Output:

tx