instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
vhZuXCsIkQR, YflCuXCsIkLu
answer:
uXCsIk


question:
HaIPcFXLhYDp, AdIPcFXtJdRE
answer:
IPcFX


question:
CMLUKSXcAomBQgGdebrvoaEe, JceePKDcAomBQgGdeomjKPOGLbB
answer:

cAomBQgGde