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

Ex Input:
lypuwWy, jRpuwcE

Ex Output:
puw


Ex Input:
sOSXbnluNuvwMETKda, JzXbnluNuvyeVHO

Ex Output:
XbnluNuv


Ex Input:
ovMsPAfviNCxEnieno, SyzxDviNCxEniJkHZaCp

Ex Output:

viNCxEni