instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
WRfFDeZjIcpidmDxtaJcv, XMxWZjIcpidmlKga
answer:
ZjIcpidm


question:
PnRypl, HvRydi
answer:
Ry


question:
LZQrNamNCtNhOL, hYeftYNamNCttAtYM
answer:

NamNCt