instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sbQJFbUtmnKaEJePFPeRM, QzfvkdZbUtmnKaEJNrWD
answer:
bUtmnKaEJ


question:
mvIvSzMtYsfVLdaGEmef, wnzMtYsfVLdaKm
answer:
zMtYsfVLda


question:
gIzhnaA, ZQzhnMC
answer:

zhn