instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sEYtoQlG, XIstoQQPw
answer:
toQ


question:
jexvmCmveGzFUimQMx, RVwOSJveGzFUimrcOwjEwe
answer:
veGzFUim


question:
dReySjyqecU, loSjyqiRl
answer:

Sjyq