instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
UQDJDbzqDxsMzUL, BxClJDbzqDxLxlngc
answer:
JDbzqDx


question:
sEYtoQlG, XIstoQQPw
answer:
toQ


question:
DggELxHpIYgIhH, BGzSuELxHpIGLaxDx
answer:

ELxHpI