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

Ex Input:
umXfmRnUgALpFAqBaKfNfo, aOAXWnUgALpFAqBmNpTCdj

Ex Output:
nUgALpFAqB


Ex Input:
OFbCjZDoRRlLsMU, DcCjZDoRRtld

Ex Output:
CjZDoRR


Ex Input:
vRhKVbWSDMDQuHVuPT, HXWlhKVbWSDMUZrq

Ex Output:

hKVbWSDM