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

Ex Input:
ugDpSMRvHM, DDwSMRvxw

Ex Output:
SMRv


Ex Input:
tyVlHfTPLRSdFilXnSfqQ, bkTPLRSdFiMgXC

Ex Output:
TPLRSdFi


Ex Input:
TzOrDSFmIavLcDi, JkLSFmIaVh

Ex Output:

SFmIa