instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
ZyrpGdXvvtrKQIxU, CLNGdXvvtrKQDpicfqLdt
answer:
GdXvvtrKQ


question:
gwVLygvd, VOQLyglfo
answer:
Lyg


question:
IECfQexqZLVO, naQexqiOBz
answer:

Qexq