instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
TvNVpHLPYjBCeUpyxlzFZ, tgKdPKVYjBCeUpyPK
answer:
YjBCeUpy


question:
TizkNtJUPHfhmGQ, enzehVkNtJUPHunpG
answer:
kNtJUPH


question:
ybmUJPcWsbhKDoBgoU, FemlcWsbhKTiBSZ
answer:

cWsbhK