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

Ex Input:
iwSQnplQZFbXQ, lHWnplQZFzswgU

Ex Output:
nplQZF


Ex Input:
rlBoVyFsYqpmmQmelGBg, iKKaIyFsYqpmmWcrKn

Ex Output:
yFsYqpmm


Ex Input:
eeAFFYzSUunqlgcPIl, LwTtuFYzSUunyDLPud

Ex Output:

FYzSUun