instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
oGaGjsaKsUpLQAg, iDGjsaKsUoYGuta
answer:
GjsaKsU


question:
haOsaSQcyodWhqQaC, BKLEUQcyodWhvVkmxBz
answer:
QcyodWh


question:
yAjhWkfXkGrJdOUFIBOwEv, pFAYrWkfXkGrJdOeWpyxguX
answer:

WkfXkGrJdO