instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
vJtmxQmHEq, yobgAtmxQmMeoLz
answer:
tmxQm


question:
UmYbssMbmsXkKQuzNasLOib, EMqlbmsXkKQuzNcyHrpZXOQW
answer:
bmsXkKQuzN


question:
UcMaLWotJEdHbkoDYzuxxs, QArUsLzdtJEdHbkoKhqkPN
answer:

tJEdHbko