instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
cxYVucnmEQopeWHrPJ, jNnOaYVucnmEQoSE
answer:
YVucnmEQo


question:
rRmkmETbjzCzZZxihrVdefxfcenJ, ogQtzAgWjKCzZZxihrVdRswMCmngp
answer:
CzZZxihrVd


question:
JUnUbvNWe, LCFUbvuJk
answer:

Ubv