instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
QRPOwtZATjDoJDdRNNSOH, wiafFMwpAjDoJDdRNNuCDZ
answer:
jDoJDdRNN


question:
QjDQjzAIsnYgNmmetl, vyqDQjzAIsnNajYEheP
answer:
DQjzAIsn


question:
UlFbUJGAHA, dqFWUJGASP
answer:

UJGA