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:
RNYHvcNnbsUdJLvS, PpNnbsUdglWhl
answer:
NnbsUd


question:
uLlpNmuAwXMi, uXlpNmuAxtKb
answer:

lpNmuA