instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
HEVqGddewrNqiZ, iyvlddewrNXr
answer:
ddewrN


question:
WRfFDeZjIcpidmDxtaJcv, XMxWZjIcpidmlKga
answer:
ZjIcpidm


question:
LgHobGeRtri, djbGeRtArPa
answer:

bGeRt