instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
wYhGWdRC, cFGWdHEy
answer:
GWd


question:
uZSRkFDHsGXNMaggxUn, lTrQKKpsGXNMaggEdSrEX
answer:
sGXNMagg


question:
ZKfYRpyPSxPGZvH, hvwVKRQyPSxPGZPLpxB
answer:

yPSxPGZ