instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
RGImMTISYdkjzMO, pmyfpImMTISYdatLBBFr
answer:
ImMTISYd


question:
rRmkmETbjzCzZZxihrVdefxfcenJ, ogQtzAgWjKCzZZxihrVdRswMCmngp
answer:
CzZZxihrVd


question:
eLwFrmrAwuqtTJAmyXuSP, xOkvQrFrmrAwuqtMDgzMvuT
answer:

FrmrAwuqt