instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
mCxQTIaXN, mWQTIaxzPT
answer:
QTIa


question:
rRmkmETbjzCzZZxihrVdefxfcenJ, ogQtzAgWjKCzZZxihrVdRswMCmngp
answer:
CzZZxihrVd


question:
UYbkWAftEFbTWhpUCbqwSFmTI, DkzXLtEFbTWhpULxO
answer:

tEFbTWhpU