instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
GnElFKBIoYmAdvz, GrElFKBIoMo
answer:
ElFKBIo


question:
CwTYJWQbzEZkvcqKn, hBnhJWQbzEZkKmVM
answer:
JWQbzEZk


question:
tstludtoUGGnhSMSPgvZfD, zCwOQrjkmGGnhSMSPgpEcnCbNv
answer:

GGnhSMSPg