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

Ex Input:
jdLbZSCzaAHGbNwILGmudOH, RdIPuEYJvUZSCzaAHGbNduLToRC

Ex Output:
ZSCzaAHGbN


Ex Input:
zBNTHKtofMdHfBgJhOfojzM, VIkVdFapofMdHfBgjPCUo

Ex Output:
ofMdHfBg


Ex Input:
BrRKVMCCqsMUDWbvvu, khDUCqsMUDWkXBR

Ex Output:

CqsMUDW