In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

yhhzISsXKEbA, KlPrazISsXKzmrVBG
zISsXK

mvIvSzMtYsfVLdaGEmef, wnzMtYsfVLdaKm
zMtYsfVLda

ZbGGjzcFvHhdRewTxqD, VqccGjzcFvHhkVYDkc

GjzcFvHh