instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
iaXeqfIrYKxPJRXxfSm, rIYKxPJRXxfsjVsqe
answer:
YKxPJRXxf


question:
uZSRkFDHsGXNMaggxUn, lTrQKKpsGXNMaggEdSrEX
answer:
sGXNMagg


question:
tbUCUtIqBiolzg, HZJXBTtIqBiolIBg
answer:

tIqBiol