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

Ex Input:
IGHhMfqLeBpnullsPInfBH, LTDBpnullsPIBynwCrCQ

Ex Output:
BpnullsPI


Ex Input:
XbjDHRCWxdPbhibUKn, SrpuPDHRCWxdPbKPWEXNWbZ

Ex Output:
DHRCWxdPb


Ex Input:
CPiUOfyZmLiWOeGVEGWQ, hjBnLTgyZmLiWOtinDab

Ex Output:

yZmLiWO