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:
rlBoVyFsYqpmmQmelGBg, iKKaIyFsYqpmmWcrKn
answer:
yFsYqpmm


question:
eNSffFTNTGQVOUTtgQxbXy, vRVlFTNTGQVOUTwfpxUxYWR
answer:

FTNTGQVOUT