instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sdGIVJPsWWszKPCGk, ghRJPsWWszKcJUg
answer:
JPsWWszK


question:
faHRBWyXsYzYmHQyy, aHTyXsYzYeXBFV
answer:
yXsYzY


question:
iupYjFXrrMqWzJSLUSwmEukHc, hqajjWrrMqWzJSLnF
answer:

rrMqWzJSL